In a small bowl, mix the cooked sushi rice with rice vinegar and sea salt until well combined and slightly tacky.
Slice the sushi-grade salmon into long, thin strips and ensure the cooked shrimp is peeled, deveined, and patted dry.
Julienne the cucumber into thin matchsticks and slice the avocado into thin, uniform wedges.
Place one nori sheet on a bamboo rolling mat and spread half of the seasoned rice evenly over the bottom two-thirds of the sheet.
Arrange half of the salmon, shrimp, cucumber, and avocado in a horizontal line across the center of the rice layer.
Carefully roll the nori from the bottom up, using the mat to maintain firm pressure, then seal the top edge with a small drop of water.
Repeat the process with the second nori sheet and remaining ingredients, then slice each roll into eight pieces using a sharp, wet knife.
Serve the fresh rolls immediately with coconut aminos, pickled ginger, and wasabi paste on the side.