Wash the chicken thoroughly with cold water, then chop into finger sized pieces.
Mix flour and cornstarch well and add a pinch of salt from the tablespoon sized amount, then dredge chicken.
Meanwhile, preheat sunflower oil.
In a medium-sized saucepan, add vinegar, water, and ketchup and stir with whisk until well blended. Bring to a boil.
After mixture boils, add sugar, salt, garlic powder, pineapple, bell pepper, and onion. (hint: if sauce is coming too thin after 10 minutes on low heat, remove from heat and add teaspoon of cornstarch gradually until thickening begins.).
Add chicken to oil and fry until golden. After chicken is fried, add immediately to sauce mixture on low heat and toss well to coat.