Set a wire rack over a baking sheet.
Add the shrimp to a medium bowl. Cover with cold water and let sit until thawed, about 10 minutes.
Drain the thawed shrimp on paper towels and pat dry.
Place the cornstarch in a large bowl. Add the shrimp and toss until well-coated.
Heat the oil in a wok or large pan until it reaches 400°F (200°C).
Add the garlic and fry for 40 seconds-1 minute, until golden brown. Remove the garlic with a strainer or slotted spoon and drain on paper towels.
Fry the shrimp, about 6 at a time, for 2 minutes, or until light golden brown. Transfer to the wire rack to drain.
In a clean wok or large pan, add the ginger and red pepper flakes and toast for 2 minutes, until the ginger is starting to brown.
Add the shrimp and toss to combine. Season with the salt and pepper and toss until well-coated.
Transfer the shrimp to a plate and garnish with the scallions and fried garlic.
Serve with rice.
