Prep the wings: Pat wings very dry with paper towels. In a large bowl, toss with baking powder (or cornstarch), salt, pepper, and oil until evenly coated.
Heat the oven: Preheat to 425°F (220°C).
Line a sheet pan with foil and set a wire rack on top. Lightly oil the rack.
Bake for crispiness: Arrange wings in a single layer. Bake 35–45 minutes, flipping once halfway, until deep golden and crisp.
Make the sauce: In a small saucepan over low heat, whisk gochujang, soy sauce, honey, rice vinegar, sesame oil, garlic, and ginger.
Simmer 2–3 minutes until glossy. Add a splash of water if too thick.
Glaze the wings: Transfer hot wings to a bowl. Pour over half the sauce and toss to coat.
Return wings to the pan and bake 5–7 more minutes to set the glaze.
Finish and serve: Toss with remaining sauce. Sprinkle with sesame seeds and green onions. Serve hot.
Air fryer option: Cook wings at 380°F (193°C) for 18 minutes, shaking halfway.
Increase to 400°F (205°C) for 5–7 minutes to crisp. Toss with sauce as above.