In a medium bowl, combine the chicken thigh pieces with 1 tbsp soy sauce, Shaoxing wine, and white pepper. Mix well. Add the lightly beaten egg white and stir to fully coat.

Sprinkle the 1/4 cup cornstarch and 2 tbsp flour over the chicken. Toss until every piece is evenly and lightly coated. Set aside to marinate for at least 10 minutes.

While the chicken marinates, prepare the sauce. In a small bowl, whisk together all the sauce ingredients: 1/4 cup soy sauce, oyster sauce, honey, rice vinegar, black pepper, sesame oil, water, and 1 tbsp cornstarch. Whisk until the cornstarch is fully dissolved and the sauce is smooth. Set aside.

Preheat your air fryer to 400°F (200°C). Lightly spray the air fryer basket with cooking oil. Arrange the coated chicken pieces in a single layer, ensuring they don't overlap (cook in two batches if necessary).

Air fry for 10-12 minutes, flipping the chicken halfway through, until it is golden brown, crispy, and cooked through (internal temperature reaches 165°F or 74°C). Set the cooked chicken aside.

Heat 1 tbsp of vegetable oil in a large wok or skillet over medium-high heat. Once shimmering, add the chopped onion and bell peppers. Stir-fry for 3-4 minutes until they are slightly softened but still have a crisp bite.

Add the minced garlic and grated ginger to the wok and cook for another 30-60 seconds until fragrant.

Give the black pepper sauce a final whisk and pour it into the wok with the vegetables. Bring the sauce to a simmer, stirring constantly. It will thicken into a glossy glaze in about 1-2 minutes.

Add the crispy air-fried chicken to the wok. Toss everything together to coat the chicken and vegetables in the sauce. Remove from heat.

Serve immediately over steamed rice, garnished with sliced green onions and toasted sesame seeds if desired.