Whisk together ¼ cup of rice vinegar, 1 tablespoon of sugar, and ½ teaspoon of salt in a small bowl until dissolved. Pour over 2 cups of cooked sushi rice and gently fold to coat without mashing the rice.

Transfer the seasoned rice into a lined baking pan and press down evenly. Cover with plastic wrap and chill in the fridge for at least 4 hours or overnight.

Chop 8 ounces of sushi-grade salmon into cubes. In a medium bowl, mix with 3 tablespoons of Kewpie mayo, 1 tablespoon of sriracha, 1 tablespoon of soy sauce, and 2 chopped scallions. Refrigerate until ready to assemble.

Cut the chilled rice into 16 equal rectangles using a sharp knife. Keep them on the lined pan.

Heat ½ inch of vegetable oil in a skillet over medium heat. Fry the rice rectangles in batches for 3-4 minutes on each side until golden brown and crispy.

Transfer the fried rice cakes to a paper towel-lined plate to drain excess oil. Top with sliced avocado, spicy salmon mixture, and jalapeño.

Sprinkle black and white sesame seeds over the assembled rice cakes. Serve warm with soy sauce or ponzu for dipping.