If you haven't already cured and cubed the salmon, full instructions can be found here. Preheat a broiler on high with a rack set just below it. Transfer the cubed salmon to a large mixing bowl.
Whisk white miso paste, sugar, mirin, soy sauce, sesame oil, ginger paste, and granulated garlic in a small bowl or measuring cup. Reserve 2 Tbsp of marinade, then pour the rest on top of the salmon. Gently toss to evenly coat. Allow this to sit.
Transfer the marinated salmon to a parchment or silicone lined rimmed baking sheet. Broil on high, rotating the pan once halfway through to ensure even cooking.
Serve salmon bites over sushi rice with reserved salmon marinade brushed on top, if desired. Garnish with avocado, scallions, cilantro, sliced cucumbers, pickled ginger, sesame seeds, and chiles, then serve immediately!