If you like a little heat in your sweet and sour chicken, this spicy version is perfect for you. The chicken is marinated in a spicy sauce made with chili paste, soy sauce, garlic, and ginger. After marinating, the chicken is stir-fried with bell peppers, onions, and pineapple chunks. The sauce is made with vinegar, ketchup, sugar, and soy sauce, but with an added kick from the chili paste. The result is a flavorful and spicy sweet and sour chicken that will leave your taste buds tingling.