Whisk the 1 ½ tablespoons soy sauce and 1 ½ teaspoons yuzu kosho together in a bowl until it's evenly mixed.
1 ½ tablespoons soy sauce, 1 ½ teaspoons yuzu kosho
Slice the 375 grams salmon into ¼-inch cubes using a sharp knife and add it to a bowl along with the 45 grams red onions, 8 grams shiokonbu, and soy sauce mixture. Stir to combine.
375 grams salmon, 45 grams red onions, 8 grams shiokonbu
Prepare a clean work surface and have the 1 batch prepared sushi rice, 12 half sheets nori, 1 pack kaiware daikon sprouts, and a small bowl of water ready.
Lay a piece of nori in front of you with the rough surface facing up. Spread a golf-ball-sized scoop of rice onto the left half, leaving the top left corner of nori uncovered. Be sure to wet your fingers in the bowl of water as needed to keep the rice from sticking to them, but don't overdo it, or the rice and nori will get soggy.
1 batch prepared sushi rice, 12 half sheets nori
Lay some kaiware sprouts in the center of the rice with the leaves pointing towards the top left corner of the nori. Add a spoonful of spicy salmon on top of the kaiware.
1 pack kaiware daikon sprouts
Carefully pick the nori up and cradle the half with the rice and filling in your left hand, folding the bottom right corner up to the center of the nori.
Wrap the top right corner of the nori, over and around the filling, making the corner meet the backside of the top left corner.
Eat the roll immediately, or the nori will lose its crispness and get chewy.