Make the Spicy Salmon: Combine diced salmon, Japanese mayo, chili sauce, soy sauce, sesame oil, maple syrup, and sesame seeds in a bowl. Mix gently until fully coated. Let sit for 5 to 10 minutes to marinate. Set aside.
Heat the Oil: Add enough neutral oil to a skillet to fully coat the bottom. Heat over medium-high until just lightly smoking.
Add the Yolk: Carefully place one egg yolk directly in the center of a dry rice paper sheet.
Fry the Rice Paper: Lower the sheet into the hot oil, yolk side up. The rice paper will puff rapidly around the yolk within 20 to 30 seconds. Cook until fully puffed and crisp with the yolk just set but still jammy. Transfer immediately to a paper towel-lined plate. Repeat with the second sheet and yolk.
Build the Tostadas: Spoon spicy salmon over one half of each puffed rice paper. Pile diced avocado and cucumber into the remaining space. Top the salmon with sliced green onion and sesame seeds. Finish the whole tostada with a drizzle of chili crisp, including over the yolk in the center.
Serve: Eat immediately while the rice paper is still aggressively crisp.
