01 - Pat the shrimp dry with paper towels. In a bowl, toss shrimp with 1/2 tsp salt, white pepper, and black pepper. Let sit for 5 minutes.
02 - Toss the seasoned shrimp in cornstarch until lightly coated. Shake off any excess.
03 - Heat the vegetable oil in a deep skillet or wok over medium-high heat. When hot, fry the shrimp in batches for 2–3 minutes per batch, until golden and crisp. Remove with a slotted spoon and drain on paper towels.
04 - Carefully pour off most of the oil, leaving about 1 tablespoon in the pan. Add garlic and chili; stir-fry for 30 seconds until fragrant but not browned.
05 - Return shrimp to the pan, add scallions, Sichuan peppercorns, and 1/2 tsp salt. Toss everything together for 1 minute over high heat until well mixed.
06 - Serve immediately with lemon wedges.