Heat vegetable oil in a deep pan over medium heat until it reaches 350°F (175°C). Carefully add corn tortillas, frying them for 1-2 minutes per side until golden brown and crispy. Use tongs to remove each tortilla and place on paper towels to drain excess oil. Sprinkle Tajin and a pinch of flaky sea salt while still warm.

In a mixing bowl, combine diced ripe avocado, sweet pineapple chunks, finely chopped jalapeño, fresh lime juice, and chopped cilantro. Gently toss until well mixed, taking care not to mash the avocado. Adjust seasoning as needed.

In another bowl, combine the sushi-grade tuna cubes with wasabi sauce, sweet chili sauce, sesame oil, and soy sauce. Stir gently to coat the tuna evenly.

Take a fried tortilla and spoon the avocado-pineapple salsa onto the center. Add a scoop of the marinated tuna mixture on top.

Sprinkle sesame seeds and additional cilantro over the top. Serve immediately while still crispy.