Tuna Mayo Rice Balls (Onigiri) are a delicious fun to eat Japanese Treat made with salted rice, stuffed with a wasabi tuna mayonnaise and then wrapped in a crispy nori (dried seaweed) leaf. (VIDEO and STEP BY STEP INSTRUCTIONS INCLUDED)
Onigiri Lovers
- Onigiri are a fun addition to a packed lunch or bento box
- Easy to make with just a handful of ingredients
- You can stuff onigiri with anything your little heart desires.
- Vegan and vegetable options are easy substitutes
- Gluten-free and dairy-free
- You can eat an onigiri with one hand while typing with the other.
- One bite into the tender rice with the earthy crunchy nori (seaweed) and creamy spicy tuna mayo and you are going to be hooked.
- Only 98 calories for one tuna mayo rice ball.
Have you ever tried a Japanese Crispy Rice Onigiri? We bet these would be delicious in the air fryer...
What is an Onigiri?
O-nigiri is sometimes called nigiri, o-musubi or rice ball. This rice ball is a very common Japanese treat formed with salted white rice shaped traditionally in triangles, stuffed and wrapped in nori. We have also seen them in Japan in other shapes as well.
You can find tuna mayo rice balls in many bento boxes an in the refrigerated section in Japan in the 7/11 stores or even a delicious Wasabi Mayo Crab Onigirazu. Perfect solution for your school or work lunches. Onigirazu are larger than an onigiri and are a full meal. Your gluten-free friends are going to love these options.
Filling Ideas
The answer is anything your little heart desires. Some people like to add salted salmon, tuna mayo, preserved plums (umeboshi), other Japanese pickles, bonito or other preserved fish, kombu (seaweed) and vegetables.
Our favorite is tuna mayo because canned tuna is an easy staple to have on hand. In addition, leftovers are great in our tuna mayo roll ups. The boys favorite is Spicy Tuna Mayo so that is what we are making today.
How to Make a Triangle Onigiri Rice Ball?
Option 1: Plastic Wrap Method
- Wet your hands and fingers and place about 3 tablespoons of your cooked salted short grain Japanese rice onto a piece of plastic wrap.
- Make a little well with your fingers and add about 1 tablespoon or less of your Tuna mayo or filling of choice.
- Using the plastic wrap, gently form the rice over your filling mixture so that no filling can be seen.
- Tightly twist the top of the plastic wrap to form a ball.
- Use your hands to shape the ball into a triangle and flatten.
- Remove the plastic wrap and wrap your tuna mayo rice ball in nori.
Option 2: Rice Mold Method
- Lightly spray your onigiri mold with a little light oil once.
- Fill the mold about ¼ of the way with your salted cooked short rice mixture.
- Add about 1 tablespoon of less of your filling mixture on top of the rice. Be careful to leave a space around the edges.
- On top of your filling, add another layer of rice to the line.
- Place the lid on top of the mold and press firmly but gently down.
- Remove the mold and wrap your tuna mayo rice ball in nori.
Alternatively, you can also free hand the shape by wetting your hands and fingers in water and press and shape your onigiri by hand. This method is difficult because the rice is sticky even if you wet your hands. However, if you like this method, go for it.
Tasty Nori (Seaweed)
Nori is dried seaweed and you can find it in several forms. Enjoying the crispy seaweed and the chewy and delicious rice ball is a delightful texture combination. The goal is to keep the nori crispy. You can learn more about Nori sheets in our essential Asian Pantry Staples list.
Most commonly, you may see nori in sheets in the Asian food section of your store. If you plan on eating your Tuna Mayo Rice Balls right away, you can just cut your nori leaves into strips and place on the onigiri right after shaping.
Please note that your nori leaves will not stay crisp for long after they are placed directly on the onigiri.
How to Make in Advance?
If you plan on making your tuna mayo rice balls the day before, it is highly recommended that you look for the individual plastic wrapped nori leaves and stickers. This method allows the rice to stay separated from the nori so that the nori stays crispy until you are ready to eat it.
How Long Do They Last?
The best is immediately. However, you can make them the night before, refrigerate and eat up to 2 days. Any longer than that and the rice gets tough or at least that is my thought on it.
How Long can Onigiri be Kept at Room Temperature?
If you are making tuna mayo rice balls, then not too long as it has mayo in it. It is better to be safe than sorry. If you are making your onigiri with umeboshi or salted cured fish, then it can stay at room temperature for up to 6 hours before consumption. If you want a rice treat that can last longer at room temperature, try our kimchi rice balls.
Should you Eat Onigiri Hot or Cold?
What do you prefer? If you like your rice warm, you can heat in the microwave for a few seconds (of course after you remove the plastic wrap). On the other hand, if you like your onigiri cold or at room temperature that is okay too. It really just comes down to your preference. Our family either eats them chilled or at room temperature.
Sprinkles and Toppings!
Actually, the fun part for us is the addition of Japanese sprinkles. No, these are not the sweet sprinkles you put on cupcakes. The Japanese sprinkles are called Furikake. There are many different types of this savory and salty and fun seasoning mix combination. Noritomago Furikake that has egg and nori is our favorite. The boys love black sesame seeds.
Is an Onigiri the Same Thing as a Sushi Roll?
Actually, no it is not. A sushi roll is made with rice that has a special vinegar, salt and sweetness that gives the rice that special flavor. Onigiri rice is generally seasoned with only salt.
- Pull down plastic on the number one.
- Slide the plastic off the number 2 section.
- Then, slide the plastic off the number 3 section.
- You may need to reposition the fresh crispy nori leaf around the onigiri.
- Enjoy!
If you liked this recipe, be sure to check out our Japanese Recipe Category page for more inspiration.
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Tuna Mayo Rice Balls (Onigiri)
Ingredients
- 2 cups sushi rice
cooked (Japanese short grain rice) - 1 teaspoon salt
- 5 ounces tuna fish
in water - 1 tablespoon mayonnaise
(we used Kewpie brand) - 1 teaspoom wasabi
(optional and adjust amount to heat desired) - 8 slices nori (dried seaweed sheets) cut into 3-4 2 inch strips or 8 onigiri wraps with stickers
- Furikake optional (black sesame seeds or Noritomago Furikake)
- Bowl of water to rinse hands
- Plastic wrap or onigiri molds
Instructions
- To prepare the rice, rinse 2 cups sushi short grained rice with water until it runs clear. You can either use a rice cooker or stove top. If cooking your rice on the stove top, add your rinsed rice and 2 and ¼ cups water to a pan and place on the lid. Steam rice over low heat for about 12 minutes or until all the water is absorbed and rice is tender. Set rice aside and let it cool.
- Add drained canned tuna, mayonnaise and wasabi to a bowl and mix well. Salt and white pepper to taste. Wasabi is completely optional. Adjust amounts up or down to desired heat level. Set aside.
Form your Onigiri
Plastic Wrap Method:
- Wet your hands and fingers and place about 3 tablespoons of your cooked salted short grain Japanese rice onto a piece of plastic wrap.
- Make a little well with your fingers and add about 1 tablespoon or less of your Tuna mayo or filling of choice.
- Using the plastic wrap, gently form the rice over your filling mixture so that no filling can be seen.
- Tightly twist the top of the plastic wrap to form a ball.
- Use your hands to shape the ball into a triangle and flatten.
Onigiri Mold Method:
- Lightly spray your onigiri mold with a little light oil once.
- Fill the mold about ¼ of the way with your salted cooked short rice mixture.
- Add about 1 tablespoon of less of your filling mixture on top of the rice. Be careful to leave a space around the edges.
- On top of your filling, add another layer of rice to the line.
- Place the lid on top of the mold and press firmly but gently down.
Free Hand Method:
- You can also free hand the shape by wetting your hands and fingers in water and press and shape your onigiri by hand. This method drives us crazy as the rice is sticky even if you wet your hands. However, if you like this method, go for it.
- Remove your tuna mayo rice balls from plastic wrap or mold.
Place Nori Leaf on Onigiri
- Option 1 – cut a sheet of nori into 3 sections and each of the 3 sections in half. Set onigiri in the middle of the nori leaf and pinch both sides to secure. If desired, dip your onigiri into Japanese Sprinkles (Furikake) such as noritomago Furikake or black sesame on the sides that do not have the nori leaf.
- Option 2 – Place your premade plastic seaweed wrappers face down with the number one at the top. Remove your enclosed stickers and make them easily accessible and ready to go near you. I like to take them off and stick them on to the side of the counter. Place your onigiri top of the triangle just under the number one and in the middle. Pull the lower half of the seaweed wrapper up to the top. Then, take the top half of the seaweed wrapper and tuck it under and around the onigiri. Next take the seaweed wrapper that is on the very bottom and pull over on an angle to create a triangle. Use the stickers to seal closed.
- Enjoy!
Video
Notes
- To eat the tuna mayo rice balls in the pre-made plastic seaweed wrappers, follow the directions on the package. First, pull down the number one in the front. Next carefully pull off to the side number 2 and then followed by 3. You may need to tuck in the nori back under the onigiri before eating.
- Onigiri are best eaten asap but can be refrigerated overnight for lunches the next day. Eat within 2 days as the rice will get firmer as they sit. You can eat onigiri chilled or at room temperature. As these onigiri have mayonnaise in them, do not leave them sitting at room temperature for too long. If you desire, you can heat up your onigiri in the microwave (obviously after you remove the plastic wrap) if you would like your rice warm.
- You can stuff your onigiri with anything your little heart desires. You can make your onigiri with vegetables or beans to make vegan. Preserved fish and umeboshi (pickled plums) are really delicious stuffed inside. If your onigiri do not have mayonnaise in them, they can sit out at room temperature for up to 6 hours.
- To keep your onigiri fresh overnight in the refrigerator, make sure you place them in a sealable container, baggie or plastic wrap so they do not dry out.
Nutrition
Jake says
I suppose there are a lot of fillers you can use if no tuna is around
HWC Magazine says
Absolutely Jake! As a matter of fact if you are out biking like you do, it might be a better option to fill with pickled vegetables, fresh veggies, Japanese pickles or even avocado.
Raul says
i used to buy these at the 7/11 in Japan
HWC Magazine says
7/11 stores in Japan have everything, don't they. Onigiri are so delicious. Now you can make them at home. We hope you give this recipe a try soon.
Karen says
These are so fun to make and your video was so fun to watch. Really helpful showing both methods. Ours don’t look as pretty as yours but they were delicious for lunch!
HWC Magazine says
Thanks so much Karen. We are delighted to hear that our videos are helpful. If you like this bento box Tuna Mayo Rice Balls idea, you may want to try our Tomagoyaki recipe too.https://www.hwcmagazine.com/recipe/japanese-egg-roll-tomagoyaki/ Take Care and stay well.