Rinse the sushi rice until the water runs clear. Cook the sushi rice according to the package instructions. 1 cup of uncooked rice will yield about 3 cups of cooked rice. Transfer the cooked rice to a shallow bowl Salt the rice and add the vinegar. Toss and set aside and allow to cool while you gather the ingredients for the roll.

Slice the nori sheets in half. You should have 12.

Working with one nori sheet at a time, add about 1/4 cup of rice to the left half of the sheet. Spread a thin layer of wasabi onto the rice if desired.

Place the sashimi-grade fish diagonally onto the rice, towards the center. Add a few pieces of cucumber, carrot, and avocado next to the sashimi. Add sesame seeds if desired.

Fold the bottom left corner over the sashimi and vegetables, and use your finger to hold it closed. Fold in the longer end of the nori to form the handroll.

Repeat with all of the ingredients and serve with sauces as desired.