Prepare the sushi rice by gently folding in the rice vinegar while the rice is still warm, then allow it to cool completely to room temperature.
Slice the sushi-grade salmon into long, thin strips and ensure the cooked shrimp are peeled, deveined, and butterflied.
Julienne the cucumber into matchsticks and thinly slice the avocado.
Place one nori sheet on a bamboo rolling mat with the shiny side facing down.
Wet your fingers slightly and spread half of the seasoned rice evenly over the nori, leaving a 1-inch border at the top edge.
Arrange the salmon strips, half of the cucumber matchsticks, and half of the avocado slices in a horizontal line across the center of the rice.
Lift the edge of the mat closest to you and roll it tightly over the filling, applying gentle pressure to create a firm cylinder.
Repeat the process with the second nori sheet, using the shrimp as the primary protein.
Use a very sharp, damp knife to slice each roll into 8 uniform pieces.
Serve the fresh rolls immediately with coconut aminos, wasabi paste, and pickled ginger on the side.