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Onigiri served 2 ways one with sprinkles and one in wrappers with a side of hot green tea.
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5 from 2 votes

Tuna Mayo Rice Balls (Onigiri)

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.
Prep Time15 mins
Cook Time15 mins
Total Time30 mins
Course: Appetizers/ Snacks, Mains
Cuisine: Japanese
Keyword: Appetizers/ Snacks, Fish and Seafood, Japanese Cuisine, Pasta, Rice and Casseroles
Servings: 8
Calories: 70kcal
Author: Healthy World Cuisine


  • 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


  • 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!


    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.


    Serving: 1g | Calories: 70kcal | Carbohydrates: 9g | Protein: 4g | Fat: 2g | Saturated Fat: 1g | Cholesterol: 7mg | Sodium: 348mg | Potassium: 32mg | Fiber: 1g | Sugar: 1g | Vitamin A: 62IU | Vitamin C: 1mg | Calcium: 3mg | Iron: 1mg