Prepare Sushi Rice: Rinse the rice under cold water until clear. Cook in a rice cooker with water. Combine vinegar, sugar, and salt in a saucepan until dissolved. Fold into rice after cooking and cool.

Set Up the Rolling Station: Lay a bamboo mat and cover with plastic wrap. Have a bowl of water mixed with rice vinegar to prevent sticking.

Assemble the Roll: Place a nori sheet shiny side down, spread sushi rice over it, then add crab, avocado, cucumber, and optional fillings.

Roll the Sushi: Gently roll using the mat, keeping it tight but not too tight. Dampen the exposed edge to seal the roll.

Add the Crunch: Brush with spicy mayo or eel sauce, then sprinkle panko or fried onions on top.

Slice and Serve: Cut into eight equal pieces with a damp knife. Plate and drizzle additional sauces if desired.