Whisk together rice vinegar, sugar and salt until sugar and salt dissolve. Drizzle the vinegar sugar mixture over hot cooked rice, and using a large wooden spoon or rice paddle, gently fold the rice until combined. It will take about five minutes. Cover and set sushi rice aside.
Place toasted nori, rice, and fillings in small bowls, on plates, and on serving platters. It is helpful to keep similar ingredients together, e.g. all the raw fish on one larger plate together, vegetarian fillings together. Let each person place about 2-4 tablespoons of sushi rice on a sheet of toasted nori, add their own fillings, and carefully "roll" into a cone.
Provide individual plates and small sauce bowls for soy sauce, wasabi, and pickled ginger to each person eating.