Combine chicken and cornstarch in a small bowl and toss to coat. Heat 2 teaspoons of sesame oil in a large deep-dish skillet over medium heat. Add chicken and stir fry 5-7 minutes or until no longer pink inside. Remove chicken from wok.
Combine soy sauce, vinegar and sugar in a small bowl. Set aside.
If necessary, add another teaspoon of sesame oil to the skillet so it is not dry. Add green onions, garlic, red pepper flakes and ginger to the wok and stir fry for 15 seconds. Add the soy sauce mixture and combine.
Return chicken to the wok and coat with sauce. Cook just until heated through. Top with additional green onions if desired and serve over white rice.
by The Savvy Kitchen