01 - Combine rinsed sushi rice and water in a medium saucepan. Bring to a rolling boil over high heat, then immediately cover with a tight-fitting lid. Reduce heat to low and simmer for 15 minutes until water is absorbed. Remove from heat and let stand, covered, for 10 minutes to complete steaming process.
02 - Whisk together rice vinegar, sugar, and salt in a small bowl until sugar fully dissolves. Transfer warm rice to a wide, shallow bowl and gently fold in the vinegar mixture using a rice paddle or wooden spatula. Fan the rice occasionally as you mix to cool to room temperature and achieve glossy texture.
03 - Moisten hands with water to prevent sticking. Shape cooled rice into 12 compact rectangular or oval patties, approximately 2 inches long and 3/4 inch thick. Arrange in a single layer on a parchment paper-lined baking sheet.
04 - Refrigerate rice patties for 20 minutes to firm up structure. This step is crucial for maintaining shape during frying and achieving optimal texture.
05 - Combine diced salmon, Japanese mayonnaise, sriracha, soy sauce, chopped green onion, toasted sesame oil, and salt in a medium bowl. Gently fold ingredients together until salmon is evenly coated. Refrigerate until ready to assemble, up to 1 hour.
06 - Heat 2 tablespoons neutral oil in a large nonstick skillet over medium-high heat until shimmering. Fry rice patties in batches without overcrowding, cooking 2 to 3 minutes per side until deep golden brown and crispy throughout. Transfer to paper towel-lined plate to drain excess oil.
07 - Top each crispy rice patty with a thin slice of avocado. Add a generous tablespoon of spicy salmon mixture on top. Sprinkle with toasted sesame seeds and finish with microgreens or snipped fresh chives.
08 - Arrange assembled pieces on a serving platter. Serve immediately with small bowls of soy sauce for dipping, while rice remains crispy and salmon is fresh.