Begin by rinsing 2 cups of sushi rice under cold water until the water runs clear, then cook according to package instructions for about 20 minutes. Fold in 3 tablespoons of rice vinegar, 1 tablespoon of sugar, and a pinch of salt while warm. Allow to cool.

Slice one cucumber and one ripe avocado into thin, uniform strips.

Lay a bamboo sushi mat covered with plastic wrap on a clean surface, place one sheet of nori shiny side down on the mat.

With moistened hands, take about 1 cup of cooled sushi rice and spread it evenly over two-thirds of the nori, leaving the top third clear.

In the center of the rice-covered nori, layer shrimp or crab, cucumber, and avocado strips, drizzling sriracha sauce if you like.

Starting from the edge closest to you, lift the bamboo mat and roll the nori away, tucking the filling tightly. Seal the edge with a dab of water.

Using a sharp knife dipped in water, slice the roll into eight even pieces and serve with soy sauce and additional sriracha.