Prepare the sushi rice by folding in the rice vinegar and sea salt while the rice is still warm, then allow it to cool completely to room temperature.
Slice the sushi-grade salmon and the cucumber into long, thin matchsticks approximately four inches in length.
Pit and peel the avocado, then slice it into thin, uniform wedges.
Place one nori sheet on a bamboo rolling mat and spread half of the seasoned rice thinly across the bottom two-thirds of the sheet.
Arrange half of the salmon, avocado, and cucumber in a horizontal line across the center of the rice layer.
Carefully roll the nori tightly using the bamboo mat, applying gentle pressure to ensure a compact roll, and seal the edge with a small dab of water.
Repeat the process with the second nori sheet and the remaining ingredients.
Use a very sharp, slightly damp knife to slice each roll into eight even pieces and serve immediately with coconut aminos, wasabi, and pickled ginger.