Season the Chicken:

In a bowl, toss the chicken pieces with 1 tablespoon olive oil, garlic powder, onion powder, 1/2 teaspoon salt, and black pepper. Using a food-safe glove, rub the seasonings into the meat thoroughly.

Coat with Cornstarch:

Add 1/3 cup cornstarch over the seasoned chicken and mix until every piece is evenly coated. Reserve.

Make the Sauce:

In a saucepan, combine water, rice vinegar, sugar, 1/2 teaspoon salt, minced garlic, red chili flakes (if using), ketchup, and 1 1/2 tablespoons cornstarch. Whisk over medium heat until the mixture reaches a gentle boil and thickens. Take off the heat and set aside.

Fry the Chicken:

Pour vegetable oil into a heavy-bottomed pot to a depth of 2 inches. Heat to 350°F (175°C). Fry the chicken in batches until golden brown. Transfer to a plate lined with paper towels.

Cook the Peppers:

Heat 1 tablespoon olive oil in a large skillet over medium heat. Add the bell pepper pieces and cook, stirring, until they reach your preferred texture (crunchy or soft).

Combine Everything:

Add the fried chicken and prepared sauce to the skillet with the peppers. Stir to combine. Cook for 2-3 minutes, stirring frequently, until everything is hot and well integrated.

Serve and Garnish:

Serve and add any desired garnishes.