Prepare the Nori: Place a piece of toasted nori, shiny side up, on a bamboo sushi mat. Using wet fingertips, evenly spread about 1 cup of prepared sushi rice over the nori, creating a nice, even layer. Then, sprinkle 2 tablespoons of tobiko evenly over the rice for that delightful burst of flavor.
Flip the Nori: Cover the sushi rice and nori with plastic wrap. Press one palm down while flipping the bamboo mat, ensuring the rice side is now facing down. Lay the mat back on the flat surface, making sure the plastic wraps the edges of the mat completely.
Add Fillings: On the edge of the nori nearest to you, lay 2 poached shrimp with their tails slightly exposed. Right next to the shrimp, evenly layer half of the julienned cucumber and half of the avocado slices for a colorful presentation.
Roll It Up: Start rolling the nori using the bamboo mat, beginning at the closest edge. Lift the mat slightly to prevent it from rolling inside, then continue until the far edge is reached. Gently pinch the roll with the mat to create a tight, compact sushi roll. Unroll the bamboo mat and carefully remove the plastic wrap before transferring it to a cutting board.
Repeat: Follow the same steps with the remaining nori, rice, tobiko, shrimp, cucumber, and avocado. After all the rolls are ready, slice each roll into 8 equal pieces using a sharp knife for a perfect presentation.
Serve and Enjoy: Present the Boston Roll pieces on a platter with soy sauce, wasabi, and pickled ginger on the side, inviting your guests to dip and savor each bite!