Rehydrate the shiitake and black fungus mushrooms in cold water. Shiitakes soak overnight if possible, or at least 3 hours. Black fungus require about 30mins - 1 hour to soak.
Dice the shiitake, the black fungus, spring onion and water chestnut into 5mm pieces. You'll want them fine so when you bite you don't get a chunk.
In a mixing bowl, mix in the pork mine, the diced ingredients, and the sauces (oyster, sesame and fish sauce).
Give it a good mix. Mix by hand until the texture is smooth and you can almost "meatball" it. The key is to get the mince to develop some texture.
Cover and leave to marinate in the fridge for at least 30 minutes.
Take your wontons wrappers out of the fridge and fan out to make it easier to separate and wrap.
Taking 1 tsp of filling, wrap using your desired shape, using water to seal.
Cook in rapid boiling water for about 3 minutes. The wontons are ready when they are floating and the wonton skin is slightly soft and starting to get transclucent.Optional: add 1tbs of neutral flavoured oil to the water to keep them from sticking once out. Serve as soup, with a chilli sauce or on top of noodles.