Prepare the sushi rice: Rinse the rice under cold water until the water runs clear. Cook with 2½ cups of water. While still warm, mix in rice vinegar, sugar, and salt, then let it cool.
Toast the panko: Heat sesame oil in a non-stick pan and toast the panko until golden brown. Set aside.
Prepare fillings: Slice avocado and cucumber; shred crab meat.
Assemble the roll: Place a nori sheet on a bamboo mat covered with plastic wrap. Spread a thin layer of rice on top, then flip it over. Add crab, avocado, and cucumber in the center. Roll tightly using the mat.
Add the crunch: Sprinkle toasted panko or tempura flakes evenly over the roll.
Slice and serve: Cut each roll into 6–8 pieces with a sharp, wet knife. Drizzle with spicy mayo and eel sauce, then garnish with sesame seeds and scallions.
