Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper. Pat the chicken wings dry with paper towels.
In a large bowl, combine the baking powder, salt, and pepper. Add the chicken wings and toss until they are evenly coated.
Arrange the wings in a single layer on the prepared baking sheet. Bake for 45-50 minutes, flipping halfway through, until the wings are cooked through and the skin is crispy.
While the wings are baking, prepare the sauce. In a small saucepan, whisk together the soy sauce, honey, hoisin sauce, rice vinegar, sesame oil, minced garlic, grated ginger, and red pepper flakes.
In a small bowl mix the cornstarch and water, then add to the sauce. Bring the sauce to a simmer over medium heat. Cook, stirring constantly, until the sauce thickens slightly, about 2-3 minutes.
Once the wings are done, remove them from the oven. Transfer the wings to a large bowl. Pour the thickened sauce over the wings and toss until they are evenly coated.
Serve the wings immediately. Garnish with sesame seeds and chopped green onions, if desired.