In a small bowl, whisk together the mayonnaise, sweet chili sauce, sriracha, and lime juice until smooth, then set aside.

Pat the prawns dry thoroughly with paper towels, then season them evenly with salt and black pepper.

Place the cornstarch in a shallow bowl and dredge each prawn, ensuring they are fully coated but shaking off any excess powder.

Heat the vegetable oil in a large skillet over medium-high heat until it is shimmering and hot.

Place the prawns in the skillet in a single layer and fry for 2-3 minutes on each side until they are golden brown and crispy.

Transfer the cooked prawns to a clean mixing bowl and pour half of the prepared sauce over them, tossing gently to coat.

Arrange the mixed greens, cucumber slices, and avocado on serving plates to create the salad base.

Top the salad with the warm, crispy prawns and drizzle the remaining sauce over the greens.

Garnish with toasted sesame seeds and serve immediately while the prawns are still crunchy.