In a mixing bowl, whisk together mayonnaise, sriracha, sesame oil, soy sauce, and lime juice until smooth. Gently fold in diced sushi-grade tuna, red onion, green onion, and toasted sesame seeds. Cover and refrigerate for at least 15 minutes.

For frying, heat about 2 inches of oil in a skillet over medium heat until it reaches 350°F. Carefully fold each wonton wrapper into a taco shape and fry for 1-2 minutes until golden brown and crispy. For baking, preheat oven to 375°F and arrange wonton wrappers draped over the edges of an oven-safe dish for 6-8 minutes until crisp.

Once wonton shells are ready, take them out and let cool slightly. Spoon a generous portion of the chilled tuna mixture into each wonton shell, topping with slices of creamy avocado and optional garnishes like jalapeños or pickled ginger.

Transfer the assembled tacos onto a serving platter and serve immediately with lime wedges and additional garnishes on the side.