Rinse the sushi rice in a fine-mesh sieve under cold water until the water runs clear, then cook with 0.5 cups of water until tender.
While the rice is still warm, gently fold in the rice vinegar and sea salt using a wooden spatula, then spread it on a plate to cool completely.
Slice the sashimi-grade salmon into long, uniform strips approximately 0.5 inches thick using a very sharp knife.
Peel the cucumber and avocado, then slice them into thin, delicate matchsticks to ensure they fit perfectly inside the roll.
Place a sheet of nori shiny-side down on a bamboo sushi rolling mat, ensuring the lines of the nori are parallel to the mat's slats.
Wet your hands slightly and spread half of the cooled rice in a thin, even layer over the bottom two-thirds of the nori sheet.
Arrange half of the salmon strips, avocado matchsticks, 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 firm but gentle pressure to create a compact, even cylinder.
Slice the roll into 8 equal pieces using a damp, sharp knife, and repeat the process with the second nori sheet and remaining ingredients.
Serve the fresh rolls immediately with coconut aminos, wasabi paste, and pickled ginger for a complete, restaurant-quality experience.