Place the chicken wings in a 9x13 baking dish and spread them out evenly. Set aside.
Mix the sauce: Combine ketchup, water, soy sauce, honey, rice vinegar, sesame oil, and minced garlic in a small pot. Stir well to combine. No need to heat it yet.
Pour half the sauce over the chicken, making sure each piece is coated. Set the remaining sauce aside for later.
Bake for 30 minutes. Flip the wings over and bake for another 30 minutes, or until the wings are golden and crispy.
Thicken the sauce: While the wings finish baking, cook the remaining sauce in the pot over medium heat for 2–3 minutes, stirring occasionally, until it thickens slightly.
Baste the wings: Remove the wings from the oven and brush them generously with the thickened sauce.
Let the wings rest for 10 minutes to soak up the flavor.
Garnish and serve: Sprinkle the wings with sliced green onions and sesame seeds before serving.