Add cornstarch and chicken pieces to a ziplock bag and shake to evenly coat.

Heat oil in a large skillet over medium-high heat.

Add chicken in 2-3 batches, cooking for several minutes on each side until golden brown and cooked through. Add more oil while cooking, if needed. Remove chicken to a plate.

Add the sauce ingredients to the pan and whisk well to combine.

Cook for a few minutes, until thickened. Add green onions and cooked chicken and toss to coat.

Serve over hot cooked rice with a few extra green onions and sesame seeds (optional) on top.