1. Cut the cabbage leaves into small pieces each roughly 2.5 x 1 cm (1/4 x 1/2 in).
2. Heat the oil in a preheated wok until smoking, then add the peppercorns and chillies.
3. Add the cabbage to the wok and stir-fry for about 1 - 2 minutes. Add the salt and sugar, continue stirring for 1 minute more, then add the soy sauce, vinegar and sesame oil. Blend well and serve immediately.