Pat the chicken wings completely dry with paper towels. Add the wings to a bowl and toss with soy sauce, Shaoxing wine, onion powder, and MSG or salt. Let the wings marinate for 30 minutes.
Preheat the oven to 400°F. Arrange the wings in a single layer on a baking sheet or wire rack. Bake for about 30 minutes, flipping halfway through.
While the wings are baking, add soy sauce, Shaoxing wine, chili flakes, Chinese five-spice powder, minced garlic, brown sugar, and rice vinegar to a saucepan. Bring to a gentle simmer and cook for a few minutes.
In a small bowl, mix ½ tbsp cornstarch with 1½ tbsp cold water to make a slurry. Slowly pour the slurry into the simmering sauce while stirring constantly. Cook for 30–60 seconds, or until the sauce becomes glossy and slightly thickened.
Remove the wings from the oven and spoon the sauce over each wing, reserving about ⅓ of the sauce for later.
Return the wings to the oven and bake for another 10 minutes, until the wings are cooked through and the glaze becomes sticky and caramelized.
Transfer the wings to a large bowl and toss with the reserved sauce until evenly coated.
Top with sliced green onions, sesame seeds, and fresh chili peppers. Serve immediately and enjoy!