Tuna Onigiri

1.Place the rice in a rice cooker insert and rinse well under cold water, rubbing the grains of rice between your fingers, until the water runs clear. Add the water and cook in a rice cooker according to the manufacturer’s directions. Once done remove from rice cooker, gently fluff the rice with a rice paddle. While the rice cools slightly, prepare the onigiri filling.
2.In a medium bowl, combine the mayonnaise, rice vinegar, and sugar. Whisk until well combined. Add tuna, wasabi, soy sauce, green onion, salt and pepper and combine with a fork until evenly combined, set aside.
3.Fill a small bowl with water. Once the rice is cool enough to handle, start assembling the onigiri. Lightly moisten your hands by dipping them in the water bowl.
4.Grab roughly a 1/2 cup of sushi rice and gently press into a thick oblong shape in one palm of your hand. Add a tablespoon of the tuna filling, pinched together with your fingertips, to the center of the rice and close the rice over the filling.
5.Gently shape the rice ball into a wide triangular shape using the palms of one hand and the fingers of your other hand, rotating the rice ball as you go.
6.Sprinkle the outside of the onigiri with furikake. Wrap each onirigi in a nori sheet moistened with water and place an additional small spoonful of tuna filling on the top of each onigiri. Serve immediately.