Thinly slice the leek, then chop the chilli and garlic.
Heat the oil in a wok. When hot, add the leek and stir-fry for a couple of minutes until tender.
Add the chilli and garlic, stir-fry for a minute.
Add the oyster mushrooms and soy sauce. Stir-fry for 2 minutes. Turn down the heat, add the lime juice and put a lid on. After 5 minutes take the lid off and add the sesame seeds. Stir for a couple of minutes, until the liquid has reduced to a thick sauce.
Turn off the heat and add the sesame oi and coriander leaves. Put the lid on and let it rest for a minute.
Serve warm with a dash of lime juice.