Place cubed pork in a medium bowl, and season with salt, sugar, and soy sauce. Mix in the egg white and green onions. Cover, and place in the refrigerator at least 1 hour.
Heat 1 quart oil to 365 degrees F (185 degrees C) in a large, heavy saucepan or deep fryer.
Coat the pork with cornstarch, and fry in the heated oil about 10 minutes, until evenly browned. Drain on paper towels.
Heat 1 tablespoon oil in a wok over medium heat. Stir in the celery, green bell pepper, and onion, and cook until tender. Season with salt and sugar. Remove from heat, and set aside.
In a small saucepan, mix water, salt, sugar, apple cider vinegar, ketchup, soy sauce, and pineapple juice. Bring to a boil. Mix cornstarch and cool water in a small bowl. Add cornstarch mixture to ketchup mixture. Add the cooked pork and pineapple chunks to celery mixture. Add sauce mix. Return to boil, and stir until well blended.