RICE: Add the cooked rice to a glass bowl. Combine the salt, rice vinegar, and sugar in a microwave-safe bowl and zap until hot. Stir to dissolve the sugar and salt. Pour the rice vinegar over the rice and combine it with a rice paddle until absorbed. Line a 9x5 baking pan with plastic wrap. Add the rice to the baking dish and spray a rice paddle with cooking spray. Press the rice paddle down on the rice to create an even layer. Cover and allow the rice to cool for at least one hour in the fridge or ideally, overnight.
SALMON: Chop the salmon on a cutting board with a sharp knife into small pieces. Add it to a medium bowl along with mayonnaise, lime juice, 1 tablespoon sriracha, toasted sesame oil, and scallions. Taste and adjust with additional sriracha if desired. Cover and refrigerate until ready to use.
FRY RICE: Cut the rice into 15 equal pieces. Wet the knife to help with cuts. Heat the oil in a large nonstick frying pan. Add as many rectangles that fit in the frying pan without overcrowding and fry for 3-4 minutes per side or until golden. Remove rice to a plate lined with a paper towel.
ASSEMBLE: In a bowl, mash together the avocado, wasabi paste, and a pinch of salt. Add a dollop of mashed avocado to each rice cake. Top with a heaping tablespoon of salmon. Lay on a sliced jalapeño or sprinkle with toasted sesame seeds and serve with sushi ginger.