Tuna Mayo Onigiri is a popular variation of Onigiri that combines the flavors of canned tuna and mayonnaise. To make Tuna Mayo Onigiri, start by mixing canned tuna with mayonnaise in a bowl. You can also add some chopped green onions or pickles for extra flavor. Next, prepare the sushi rice and shape it into small triangular or round balls. Place a spoonful of the tuna mayo mixture in the center of each rice ball and shape it into a triangle or round shape. Finally, wrap the Onigiri with a strip of nori seaweed. Tuna Mayo Onigiri is a delicious and satisfying snack that is perfect for lunchboxes or picnics.