Pat the sushi-grade salmon dry with a paper towel and ensure it remains chilled until ready to slice.
Slice the salmon into long, thin strips approximately half an inch thick using a very sharp knife.
Place the cooked sushi rice in a small bowl and gently fold in the rice vinegar until well combined.
Lay the nori sheet on a bamboo rolling mat with the rough side facing up.
Wet your fingers slightly and spread the seasoned rice evenly over the nori, leaving a one-inch border at the top.
Arrange the salmon strips, avocado slices, and cucumber matchsticks in a horizontal line across the center of the rice.
Using the bamboo mat, roll the nori tightly over the fillings, applying gentle pressure to create a firm cylinder.
Use a damp, very sharp knife to slice the roll into eight even pieces to ensure clean, precise cuts.
Serve the rolls immediately with coconut aminos, pickled ginger, and wasabi paste on the side.