Wash the pak choy well. Heat a wok. Add a little oil. Add ginger and stir fry for half a minute. Add garlic and continue to sate. Add pak choy and toss.
Blend cornflour in a little water. Add soy sauce, salt, sugar and half a cup of water to the wok and cook.
Remove the pak choy pieces and place them in a serving bowl. Add cornfour to the wok and cook till the sauce thickens. Pour over the pak choy.
Drizzle sesame oil and serve hot with steamed rice.