Give the king prawns a good wash in ice cold water, then with a very sharp knife slice the back of the prawn and remove the vein (digestion tract). Rinse again in ice-cold water and drain.
Heat a wok over a high heat, add oil, then ginger. Stir for a few seconds until you can smell the fragrance of the ginger. Add king prawns carefully to avoid the oil spitting. Stir constantly over medium heat until the prawns begin to turn orange. Now you can add the minced garlic and stir-fry for 20 seconds, then add the tomato ketchup, sugar, Chinese rice wine and soy sauce and stir-fry until the sauce is dry enough to cling to the shrimp.
Remove from heat and serve hot.