In a small bowl, whisk together soy sauce, oyster sauce, sesame oil, and cornstarch until smooth.
Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat.
Add chicken pieces and cook until browned and cooked through, approximately 5-6 minutes; remove chicken and set aside.
Add the remaining 1 tablespoon of oil to the pan, then add zucchini and cook for 3-4 minutes until crisp-tender.
Stir in the garlic, ginger, and red pepper flakes; cook for 30 seconds until fragrant.
Return the chicken to the pan and pour the sauce over the mixture.
Toss continuously for 1-2 minutes until the sauce has thickened and coated all ingredients evenly.
Serve immediately.