Traditionally, onigiri are made with plain rice, but I like to use sushi rice seasoned with rice vinegar, sugar, and salt just because, well, it’s even more delicious. Fill your onigiri with whatever fillings you desire. See my post for a list of ideas. (Onigiri are intended to be kept at room temperature for several hours, so using raw fish as a filling is not recommended (of course, if you’re planning to eat your onigiri soon after preparing them, feel free to disregard this advice). Here…