Tuna Mayo Rice Balls (Onigiri) are a delicious fun to eat Japanese Treat made with salted rice and stuffed with a wasabi tuna mayonnaise and then wrapped in a crispy nori leaf. (VIDEO and STEP BY STEP INSTRUCTIONS INCLUDED)
You are going to love Tuna Mayo Rice Balls because…
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 the heck is a 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 will see tuna mayo rice balls in many bento boxes an in the refrigerated section in Japan in the 7/11 stores. . If you have not tried our Wasabi Mayo Crab Onigirazu, you are going to love this in your school or work lunches. Onigirazu are larger than an onigiri and are a full meal. Our gluten-free friends are going to love these options.
Grab your onigiri at your favorite 7/11 or convenience stores
Have you ever been to Japan and visited a convenience store? You can find onigiri in so many flavors from everything to salmon, tuna mayo, umeboshi (preserved plums), and even some plain with anuki beans threaded within the rice. When you are on the go waiting for your train to arrive or waiting for the bus or have no time to pack a work or school lunch, 7/11and Lawson’s comes to the rescue. Be sure to pick up some miso fish balls and tea too.
What do you put inside an onigiri rice ball?
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. The boys favorite is Spicy Tuna Mayo so that is what we are making today.
How to make a triangle onigiri rice ball?
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.
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.
- Remove the mold and wrap your tuna mayo rice ball in nori.
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.
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.
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.
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. We bought ours at a Korean market near us. However, you can also order them online on amazon. This is not a sponsored post or affiliate marketing. We just wanted to let you know how to find the supplies to make it easier for you. This one has the wrappers and the onigiri mold, if you are interested.
How far in advance can you prepare onigiri?
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. In Japan, we used to have these little packs that you place in the freezer to keep your food cool for lunches and picnics.
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 cold or at room temperature.
Don’t forget the 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.
How to open up an onigiri in the wrapper when the directions are all in Nihongo (Japanese)?
- 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.
Some of our more popular Japanese recipes are…
Jenga Japanese Sweet Potato Fries
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Tuna Mayo Rice Balls (Onigiri)
Ingredients
- 2 cups sushi rice
cooked (Japanese short grain rice) - 1 tsp salt
- 5 oz tuna fish
in water - 1 tbsp mayonnaise
(we used Kewpie brand) - 1 tsp 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!
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!
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.