Prep the shrimp: Pat the shrimp very dry with paper towels. Excess moisture prevents crisping.
If using shell-on, leave tails and shells on for more crunch; otherwise, peel for easier eating.
Preheat the air fryer: Set it to 400°F (200°C) for 5 minutes. A hot basket gives you better browning and texture.
Mix the seasoning: In a small bowl, combine salt, black pepper, white pepper, garlic powder, onion powder, and sugar. Stir well to distribute evenly.
Coat the shrimp: Toss shrimp with oil, then sprinkle over the seasoning mix and cornstarch.
Mix until each piece is lightly coated. The cornstarch should cling without clumping.
Load the basket: Arrange shrimp in a single layer in the hot basket. Work in batches if needed. Do not overcrowd—space is key to crisping.
Air fry: Cook for 5–7 minutes, flipping halfway.
Shrimp should be opaque, curled, and lightly golden with crisp edges. Shell-on shrimp may take the full 7 minutes.
Make the aromatic finish: While the shrimp cooks, heat a small skillet over medium with a teaspoon of oil. Add minced garlic and sliced chilies.
Sauté 30–45 seconds until fragrant. Stir in half the scallions and turn off the heat.
Toss and serve: Transfer hot shrimp to a bowl. Add the garlic-chili mixture and remaining scallions.
Toss to coat. Squeeze over lime and garnish with cilantro or sesame seeds if you like. Serve immediately.