Blanch the greens for 3-4 minutes in boiling, salted water, then refresh them in cold water and drain. Heat the sesame oil in a wok or thick-bottomed pan. Fry the garlic, ginger and chilli for a few seconds then add the spring onions and greens. Cook on a high heat for 2-3 minutes. Add the coriander to the greens, pour in the soy, toss, check the seasoning and serve immediately.