Add the sliced chicken thighs to a stand mixer along with the ingredients for the marinade. Mix the sauce with the chicken using the hook attachment for 20 minutes.
To make the teriyaki sauce, add all of the ingredients except the cornstarch and water into a small saucepan and whisk together. Bring to a boil on medium heat, stirring often.
Cook the chicken by placing it in a hot skillet with some oil (working in batches). Let it cook on both sides while spooning some of the teriyaki sauce over top.