Add buttermilk and shrimp to a bowl, ensuring shrimp is submerged. Let sit for 10 to 15 minutes.

In a shallow bowl, combine breadcrumbs, salt, pepper, garlic powder, and smoked paprika. Add cornstarch to a separate shallow bowl.

Remove a few shrimp at a time from the buttermilk. Dredge each shrimp in cornstarch, shaking off any excess. Coat in the breadcrumb mixture, pressing gently to ensure the coating sticks. Set aside on a plate. Repeat with the remaining shrimp.

Preheat the air fryer to 390°F. Spray the air fryer basket with cooking spray and arrange the shrimp in a single layer without overcrowding. Cook for 3 minutes, flip, and cook for an additional 3 minutes until crispy. Cook in batches if needed.

In a large mixing bowl, combine mayonnaise, sweet chili sauce, and sriracha to make the Bang Bang Sauce. Toss the cooked shrimp in the sauce until evenly coated.

Garnish with chopped green onions and serve with rice, if desired. Enjoy!