Preheat the oven to 350°F (180°C), or 320°F (160°C) fan-forced. Cut the corn tortillas into small 2 1/2-inch circles. Microwave them for about 30 seconds to soften.
Spray one side of each tortilla circle with olive oil and lightly season with salt. Turn a muffin pan upside down and gently shape the tortilla circles between the muffin cups to form mini taco shells. Spray the tops lightly with olive oil.
Bake for 12–13 minutes, until golden and crispy. Let the taco shells cool completely in the pan so they hold their shape.
Add the diced salmon, green onion, Kewpie mayo, sriracha, sesame oil, black sesame seeds, and salt to a bowl. Gently mix until the salmon is evenly coated. Keep refrigerated until you're ready to assemble the tacos.
Spoon about 1 teaspoon of the salmon mixture into each crispy taco shell.
Top each taco with a few pieces of diced avocado and a sprinkle of black sesame seeds. Serve with fresh lime wedges right away while the shells are still crispy.