In a large bowl, mix the cornstarch, sugar, five-spice powder, 1 tsp. salt, and 1 tsp. pepper. In a small bowl, mix the garlic, chile, and scallions; set aside.

Pat the shrimp dry with paper towels. Line a small baking sheet or large plate with a double layer of paper towels. Add the shrimp to the cornstarch mixture and toss until evenly and thoroughly coated.

In a heavy-duty 12-inch nonstick skillet, heat 1-1/2 Tbs. of the oil over medium-high heat until very hot. Add half of the shrimp in a single layer. Cook without disturbing until deep golden and spotty brown on one side, about 2 minutes. Using tongs, quickly flip each shrimp and continue to cook until the second sides are spotty golden brown, about 1 minute longer. (The shrimp may not be cooked through at this point.) Transfer the shrimp to the prepared sheet. Add another 1 Tbs. of the oil to the skillet and repeat with the remaining shrimp, transferring them to the sheet when done.

Reduce the heat to medium and add the remaining 1 Tbs. oil to the skillet. Add the garlic mixture and cook, stirring constantly, until the chile and scallions are softened andthe garlic is golden and smells toasted, about 1 minute. Return the shrimp to the pan and stir to combine. Serve immediately, with the lime wedges.