Marinate the shrimp: Pat the shrimp dry.
Place them in a bowl with the buttermilk and a pinch of salt. Let sit for 10–15 minutes while you make the sauce.
Mix the sauce: In a small bowl, whisk together the mayonnaise, sweet chili sauce, sriracha, honey, rice vinegar, garlic powder, and a pinch of salt. Taste and adjust heat or sweetness.
Set aside.
Prep the coating: Add cornstarch to a shallow dish. Remove shrimp from the buttermilk, letting excess drip off. Dredge each shrimp in cornstarch, shaking off the extra.
Place coated shrimp on a plate.
Heat the oil: In a deep skillet or pot, pour in 1–1.5 inches of oil. Heat to about 350°F (175°C). If you don’t have a thermometer, the oil is ready when a pinch of cornstarch sizzles immediately.
Fry in batches: Add shrimp in a single layer without crowding.
Fry 1–2 minutes per side, until golden and just cooked through. Transfer to a wire rack or paper towels. Sprinkle with a little salt while hot.
Toss with sauce: In a large bowl, gently toss the hot shrimp with just enough sauce to coat.
Don’t drown them—extra sauce can be served on the side.
Serve right away: Arrange over shredded cabbage or lettuce. Top with sliced green onions and sesame seeds if you like. Enjoy while crisp and warm.