Prepare the Chicken: Season the chicken strips with salt, pepper, and cornstarch, tossing to coat evenly.
Heat the Pan: In a large skillet or wok, heat vegetable oil over medium-high heat. Add the chicken and cook for 4-5 minutes until golden brown. Remove from the pan and set aside.
Sauté Aromatics: In the same pan, add garlic, ginger, and scallions. Stir-fry for 30 seconds until fragrant.
Make the Sauce: In a small bowl, mix soy sauce, oyster sauce, sesame oil, sugar, and water. Pour the sauce into the pan and stir well.
Combine & Cook: Return the chicken to the pan, tossing everything together. Cook for another 3-4 minutes until the sauce thickens and coats the chicken evenly.
Serve: Transfer to a plate and enjoy hot with rice or noodles.