In a mixing bowl, combine the chicken strips with cornstarch, 1 tablespoon of soy sauce, and 1 tablespoon of oyster sauce. Toss until the chicken is well coated.
Heat 1 tablespoon of sesame oil in a wok or large skillet over medium-high heat. Add the chicken in a single layer and cook for 3-4 minutes until browned and cooked through. Remove from the wok and set aside.
In the same wok, add the remaining tablespoon of sesame oil. Add the sliced green bell pepper, celery, and yellow onion. Stir-fry for about 3-4 minutes until tender-crisp.
Add ginger paste and garlic paste to the vegetables and stir-fry for an additional minute until fragrant.
Return the cooked chicken to the wok. Add remaining soy sauce, oyster sauce, rice vinegar, water, honey, and black pepper. Toss everything together until well combined and heated through, about 2 minutes.
Serve your Black Pepper Chicken over cooked white rice, garnished with thinly sliced green onions if desired.