Make the marinade by mixing together the sugar, salt, soy sauce and cornflour slurry. Mix in the chicken, stir to coat and allow to marinate for 20 minutes.
Meanwhile, make the sauce by mixing together the sugar, soy sauce, tomato ketchup, Worcestershire sauce and water. Set aside.
Blanch celery in boiling water for 3-4 minutes. Drain and set aside.
In a large frying pan, heat 1 tablespoon oil over high heat. Stir fry the garlic until aromatic, 2-3 minutes. Add the onions with salt and stir fry until soft, 3-4 minutes. Add the chicken, stir fry for 3-5 minutes. Stir in the red wine, if using.
Add the celery, sauce and tomatoes. Quickly mix the ingredients and cook for 3-4 minutes. Add just enough cornflour slurry to thicken the sauce, then serve.