Rinse sushi rice under cold water until the water runs clear. Cook with equal parts water according to package instructions.

Slice the avocado into strips and julienne the cucumber into matchsticks.

Lay a bamboo mat flat and position a sheet of nori on top. Wet hands and spread a layer of sushi rice over the nori, leaving about one inch at the top.

Layer the imitation crab, avocado strips, and cucumber in the center of the rice-covered nori.

Roll tightly from the bottom edge using the bamboo mat for support, sealing the roll with water on the exposed nori edge.

Slice the rolls into bite-sized pieces with a sharp knife, wiping the knife with a damp cloth between cuts.