Marinate the chopped chicken cubes with ginger garlic paste, egg, cornflour, salt, and pepper. Mix well, cover and set aside for 15-20 minutes.
Cut the onions, and bell peppers into 1-inch cubes set aside. Also, cut the pineapple slices into small chunks.
In a wok, heat oil, saute onions on medium heat, for about a minute. Remove in a plate and set aside.
Add bell peppers, saute for another minute on medium heat. Set aside.
Next, add marinated chicken in batches, don't overcrowd the wok. Fry on medium heat until golden brown. Drain on an absorbent paper napkin, set aside.
To prepare the sauce, in the same wok, remove excess oil, keeping only about 1 tablespoon of oil. Add ginger garlic and saute on medium heat until fragrant.
Next, add the ketchup, pineapple juice, vinegar, hot sauce and sugar, mix well. Bring to a boil.
In the meantime, mix 2 tablespoon cornstarch in about 1/2 cup cold water. Add this to the wok, keep stirring continuously until the sauce thickens.
Now add the sauteed veggies, pineapple chunks, and chicken pieces. Toss to coat well with the sauce. Serve hot with noodles/ steamed rice or with fried rice :D