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Tuna Mayo Onigiri (Japanese "Sea Chicken" Rice Balls)

Prep Time15 minutes
Total Time15 minutes
Author Yuto Omura
Servings 6 rice balls

Ingredients 
 

Instructions 

  • Place a colander or sieve over a bowl and squeeze the excess liquid out of 80 g canned tuna.
    squeezing excess liquid out of canned tuna
  • Pour away the liquid and place the tuna into a bowl. Mix with 1 tbsp Japanese mayonnaise, 1 tsp Japanese soy sauce (koikuchi shoyu) and 1 pinch ground black pepper.
    tuna mixed with mayo and seasonings in a red bowl
  • Sprinkle the onigiri mold with salt and fill half way with rice. Make a dent in the center and add about 2-3 tsp of tuna mayo filling. If shaping by hand, wet your hands with cold water and sprinkle with salt. Take 100-120g of rice and press it flat before placing the filling in the middle.
    Japanese white rice in an onigiri (rice ball) mold with tuna mayo filling in the center
  • If using a mold, fill the rice to the top and sprinkle the surface with a pinch of salt. Push the lid down on the top to shape, then remove the onigiri from the mold.
    Tuna mayo filling wrapped with rice in a plastic onigiri mold
  • If shaping by hand, fold the rice over to wrap the filling. Fold your palm and press the rice into a triangle shape. Turn and gently press the corners until the rice feels stable.
    a moving image showing how to add fillings to onigiri rice balls
  • Wrap each onigiri with nori and serve immediately. Enjoy!
    Tuna mayo rice ball wrapped with nori held in hand

Notes

Keep the filling to 2-3 tsp per ball: Pile on more and the rice around it stretches too thin to close over the filling, and the ball turns soggy. If it looks like too much, go with less.
If the filling turns loose: Spread it in a frying pan and heat it for about 1 minute to cook off the moisture. Cool it, then use a little less than usual in each ball.
Shape the rice while it is warm enough to hold: Cold rice will not stick to itself, and rice that is too hot gets crushed as you shape it. At 50-60°C (122-140°F) you can hold it and the grains still cling together.
Salt goes on the outside: Add no salt to the filling. The salt from the mold or your hands seasons only the surface of the rice. When you plan to eat the rice balls cold, salt the outside a touch more.
Wrap the nori when you eat: The sooner nori goes onto warm rice, the more steam it absorbs and the limper it gets. To take rice balls with you, pack the nori separately.
Use Japanese short-grain rice: Jasmine and other long-grain rice are not sticky enough to hold a triangle. In the US, California-grown short-grain rice such as Tamaki Gold works well. If you cannot find it, Korean rice is the closest match.
If you cannot find Kewpie: To 1 tbsp of regular mayonnaise, add a few drops of rice vinegar and a pinch each of sugar and dashi granules. It will not taste quite like Kewpie, but the tang and the umami come closer.