Pat the shrimp completely dry with paper towels and place them in a medium bowl. Keep refrigerated while preparing the marinade.
In a small mixing bowl, whisk together garlic, ginger, honey, soy sauce, fish sauce, and crushed red pepper flakes until smooth.
Pour the marinade over the shrimp. Toss until all shrimp are evenly coated. Cover the bowl with plastic wrap and refrigerate for 30–45 minutes, tossing once halfway through.
Heat a large nonstick skillet over high heat until just smoking. Add vegetable oil and swirl to coat.
Using tongs, place the shrimp in a single layer in the skillet, letting excess marinade drip back into the bowl (reserve marinade). Sear for 2 minutes without moving them.
Flip the shrimp and immediately pour in the reserved marinade. Cook for 1 minute, stirring gently.
Turn off the heat, flip shrimp once more, and let them sit in the skillet for 1 minute to allow the sauce to thicken into a glaze from the residual heat.
Garnish with green onion before serving.