Prepare the Marinade: In a mixing bowl, combine oyster sauce, soy sauce, hoisin sauce, honey, minced garlic, grated ginger, sesame oil, and chili flakes. Whisk until well-blended.
Marinate the Wings: Place the chicken wings in a large bowl or resealable plastic bag. Coat the wings thoroughly with the marinade. Allow them to marinate in the refrigerator for at least 2 hours, ideally overnight, for best results. Marinate in the refrigerator for at least 2 hours, preferably overnight.
Preheat the Oven: Preheat your oven to 400°F (200°C). Line a baking sheet with parchment paper.
Bake the Wings: Arrange the marinated wings on the prepared baking sheet. Bake in the preheated oven for 25-30 minutes, turning them halfway through, until the wings are golden brown and crispy.
Prepare the Sauce: While the wings are baking, pour the remaining marinade into a saucepan. Bring it to a simmer over medium heat, stirring occasionally, until it thickens slightly.
Coat the Wings: Once the wings are done baking, transfer them to a large bowl. Pour the thickened sauce over the wings and toss to coat evenly.
Garnish and Serve: Arrange the coated wings on a serving platter. Sprinkle with chopped green onions and sesame seeds. Serve hot and enjoy!