Place nori sheet on bamboo mat, shiny side down. Dampen your fingers in water. Spread a thin layer of sushi rice over the seaweed, do not cover completely. Leave a 1-inch margin at the ends uncovered to seal the roll.
Spread some mayonaise over the rice. Lay salmon, avocado,omelette and cucumber lengthwise.
To roll; slowly fold the end of the mat closest to you over the filling and tuck it in.
Use medium pressure to create compact tube. Remove the mat from around the roll, press in the loose ends and place it on a cutting board, seam side down.
Using a wet, sharp knife, slice the roll in half then in 6 equal pieces.
Serve with wasabi, soy sauce and pickled ginger.