01 - Rinse the sushi rice under cold water until the water runs clear.
02 - Combine rice and water in a rice cooker or saucepan. Cook according to rice cooker instructions or bring to a boil, then reduce heat, cover, and simmer for 18–20 minutes.
03 - In a small bowl, mix rice vinegar, sugar, and salt. Heat slightly until dissolved.
04 - Transfer cooked rice to a large bowl. Gently fold in vinegar mixture while fanning the rice to cool it. Set aside.
05 - Place a bamboo sushi mat on a clean surface. Cover with plastic wrap (optional for easier cleanup).
06 - Place a sheet of nori, shiny side down, on the mat.
07 - With wet hands, spread a thin, even layer of rice over the nori, leaving a 1-inch strip at the top uncovered.
08 - Sprinkle rice lightly with sesame seeds.
09 - Flip the nori over so the rice side is down (for inside-out rolls).
10 - Arrange a line of crab, avocado, and cucumber across the center.
11 - Roll tightly using the sushi mat, pressing gently to shape. Seal the edge with a little water.
12 - Using a sharp, wet knife, slice each roll into 6–8 pieces.
13 - Serve immediately with soy sauce, pickled ginger, and wasabi.