Prepare the Sushi Rice:
Rinse the sushi rice 4-5 times until the water is clear. Combine the rice and water in a rice cooker or cook on the stove.
In a small bowl, mix together the salt, rice vinegar, sugar, and sesame oil until the sugar dissolves.
Once the rice is cooked, toss it with the vinegar mixture in a large bowl until well combined.
Shape and Chill the Rice:
Line a small square baking tray with plastic wrap and press the seasoned rice into a 1/2-inch thick block.
Wrap the rice and refrigerate for at least 3 hours or overnight to dry out slightly, making it easier to cut.
Fry the Rice:
After chilling, cut the rice into bite-sized rectangles and pat dry.
Heat 1/4-1/2 cup of vegetable oil in a skillet over medium-high heat.
Fry the rice pieces for about 2 minutes per side until golden brown and crispy.
Place the crispy rice on a wire rack over a lined baking sheet to drain excess oil.
Prepare the Salmon:
In a mixing bowl, combine the chopped salmon, Kewpie mayonnaise, yuzu kosho, yuzu juice, soy sauce, and sesame oil. Mix until thoroughly combined.
Assemble:
Top each crispy rice piece with thin slices of cucumber.
Add 1-2 tablespoons of the spicy salmon mixture on top.
Garnish with toasted sesame seeds and chopped green onions. Serve immediately!