Sprinkle chicken with salt and coat with egg, then biscuit mix. Fry chicken in hot oil (400 degrees) until golden brown. Remove and drain on paper towel. Place in a 250-degree oven to keep warm.
Combine sugar, cornstarch, and paprika in a 10-inch skillet. Drain pineapple (reserve juice, adding enough water to make 2 cups liquid). Add pineapple juice, soy sauce and vinegar to cornstarch mixture. Cook stirring constantly until it boils, about 1 minute.
Add green pepper and onion. Cover and cook until tender and crisp, about 3-4 minutes. Add pineapple and tomatoes. Heat well. Add chicken. Serve with rice.