Skip this step if using green cabbage or chives. Wash your leafy greens (such as Bok choy or Shepherd's Purse) and blanch them in a pot of boiling water to soften. Rinse under cold water to cool, and then press slightly to remove excess water. Chop up the leafy greens. Set aside.
If using green cabbage or chives, chop into fine pieces, about 1/4 inch or less in length. Set aside.
Mix all the ingredients (except for the dumpling wrappers) in a large bowl. Mix thoroughly by hand for 10-12 minutes until the mixture forms a paste. The paste should stick together, otherwise it will be difficult to wrap the dumpling as bits of filling may fall out.
Make a taste-test dumpling. Wet the edge of half of the wrapper. Put a little filling in, less is better. Fold the dumpling up. Cook the dumpling in a pot of bowling water, or chicken stock. When the dumpling floats it is ready. Adjust the seasoning of the mixture to suit your tastes, and continue wrapping.
If you aren't eating the dumplings right away, I recommend that you place the uncooked dumplings on a baking sheet lined with parchment paper. Dumplings should be a single layer, so they don't stick together. Pop the baking tray in the freezer. After 1-2 hours, you can transfer the dumplings to a ziploc bag and store in the freezer. Now the dumplings won't stick together, and you can enjoy them whenever.