Preheat the oven to 425°F. Line a baking dish with parchment or foil. Place the chicken in the baking dish and set aside.
In a medium saucepan, whisk together the cornstarch, water, sugar, soy sauce, apple cider vinegar, garlic, ginger, sesame oil, and sesame seeds. Bring the mixture to a simmer over medium-high heat. Simmer for 3-5 minutes, or until thickened.
Remove the sauce from the heat and pour it over the chicken, covering the chicken completely. Bake for 25-30 minutes, or until the chicken is cooked through. Serve over rice.