In a bowl, mix the sliced chicken with soy sauce and cornstarch until well coated. Let marinate for about 10 minutes.

In a small bowl, combine soy sauce, rice vinegar, hoisin sauce, chili paste, sugar, sesame oil, minced garlic, and minced ginger.

In a spacious skillet or wok, warm 1 tablespoon of vegetable oil over medium-high heat. Introduce the marinated chicken and sauté, stirring frequently, until the pieces are golden brown and fully cooked, which should take around 3 to 4 minutes.

Once done, take the chicken out of the pan and keep it aside.

In the same skillet, if necessary, incorporate an additional tablespoon of vegetable oil.

Toss in the sliced red and green bell peppers, along with the onion and dried red chilies (if desired).

Stir-fry for 3 to 4 minutes, allowing the vegetables to soften slightly while retaining a crisp texture.

Add the previously cooked chicken back into the skillet with the vegetables.

Drizzle the prepared sauce over the entire mixture and mix thoroughly to ensure everything is evenly coated.

Continue cooking for an additional 2 to 3 minutes, allowing the flavors to blend beautifully.

Garnish with chopped green onions and serve hot over steamed rice.