Prepare the Chicken: Slice chicken into thin strips and season with a pinch of salt and pepper.
Blanch the Green Beans: Bring a pot of water to a boil, add green beans, and cook for 2 minutes. Drain and set aside.
Cook the Chicken: Heat 1 tablespoon of vegetable oil in a wok or skillet over medium-high heat. Add chicken and cook for 4-5 minutes until golden brown. Remove and set aside.
Stir-fry Aromatics: In the same pan, add the remaining 1 tablespoon of oil. Sauté garlic and ginger for 30 seconds until fragrant.
Add Green Beans & Sauce: Return green beans and chicken to the pan. Stir in soy sauce, oyster sauce, hoisin sauce, rice vinegar, and black pepper.
Thicken the Sauce: Pour in the cornstarch slurry and stir until the sauce thickens, coating the chicken and beans evenly.
Finish & Serve: Drizzle with sesame oil (if using), serve hot over rice, and enjoy!