1. Cook the rice in salted boiling water, drain it, then pour vinegar and sesame seeds over it. Mix well. Cover the ice cube tray with plastic wrap.
2. Peel the avocado and cut thin slices using a vegetable peeler. Cut the surimi, smoked salmon slice, and tuna into pieces, chop the chives, and shell the shrimp.
3. Place avocado slices and a piece of surimi in 8 compartments. In another 8 compartments, put pieces of smoked salmon and cream cheese. In the next 8 compartments, place chives and pieces of tuna. Fill the remaining 8 compartments with shrimp and mayonnaise.
4. Finish filling all the compartments with rice and refrigerate for 30 minutes. Unmold onto a cutting board and remove the plastic wrap. Enjoy by dipping the sushi in soy sauce.