Basic California Roll

Slice the ends off of the cucumber, then cut into quarters lengthwise. Thinly slice each quarter lengthwise to make spears.

Stir chopped crab sticks and mayonnaise together in a small bowl.

Lay 1 sheet of nori on a bamboo mat. Pat a thin, even layer of rice over the nori with wet hands, leaving a 1/3-inch edge at the bottom. Sprinkle rice with sesame seeds. Carefully flip over.

Add 1 tablespoon of the crab mixture in a line across the sheet about 1/3 of the way from the top. Layer with 1 to 2 cucumber spears and 1 to 3 slices of avocado.

Using the bamboo mat, roll the sheet tightly into a cylinder, starting at the top edge. Moisten the uncovered edge with water and finish rolling once you reached the bottom. Repeat with the remaining ingredients.

Slice each roll into 3/4-inch pieces. Garnish each piece with 1/8 teaspoon tobiko.