Whisk mayonnaise, sweet chile sauce, and Sriracha hot sauce together in a bowl. Set aside.
Place cornstarch in a shallow bowl. Gently press shrimps into cornstarch to coat; shake off any excess.
Heat oil in a deep-fryer or large saucepan to 375 degrees F (190 degrees C).
Working in batches, cook the shrimp until they are lightly browned on the outside and no longer transparent in the center, about 3 to 5 minutes.
Transfer shrimp to paper towels to drain.
Put cooked shrimp in a bowl and pour chile sauce mixture over the shrimp; toss gently to coat.
Line a serving bowl with lettuce leaves. Pour shrimp into bowl and top with chopped green onion.
