In a large bowl, toss chicken strips with toasted sesame oil and white pepper. Marinate for 10-15 minutes.

In a small bowl, stir together rice vinegar, soy sauce, dark soy sauce, Chinese rice wine (if using), brown sugar and cornstarch. Set aside.

Heat a wok or large frying pan over high heat. Add 1 tbsp of oil. When the oil is hot, add the chicken pieces, spreading it out as much as possible. Sear for 1 minute without stirring until the edges are lightly browned, then stir to cook all sides until just cooked through - about 2-3 minutes more. Transfer chicken to a bowl and set aside.

Reheat the same wok, swirl in another tablespoon of oil, add in garlic, ginger, and red chili flakes. Stir-fry over low heat for about 10-15 seconds, or until aromatic, taking care not to burn the garlic. Turn up the heat to high, add in snow peas and red onion, and stir-fry for another 30 seconds. Add in red bell pepper, and cook for one minute – making sure to stir and toss the ingredients well. When the vegetables are bright and almost crisp-tender, stir in the cooked chicken. Then take the prepared sauce, give it a stir, and quickly pour it into the wok, cooking until the sauce thickens. Add in one or two tablespoon of water if needed, toss well, and cook for a further 30 seconds or the mixture is hot and bubbly. Turn heat off, and transfer to a serving plate. Serve hot with steamed rice (brown rice is best).