When cool enough to handle, finish mixing with your hands until dough holds together.
Wrap in plastic and refrigerate until chilled through.
Work one piece of dough at a time; pinch off a walnut-sized chunk, shape into a ball, knead several times, then roll flat on a floured board.
Place dough circle in the palm of your hand; in the middle of the dough, place about 1 tbsp filling. Bring up edges and seal at top with little gathers.
Leave a tiny hole at top for steam to escape during cooking.
Line steamer or bottom of skillet with kale leaves.
Top with a layer of dumplings and steam over boiling water 15 to 20 minutes.
If using a skillet use just enough water to cushion the Mo-Mos; replenish water as needed.
Serve immediately, pairing Mo-Mos with soy sauce, ginger, and vinegar. May also be served with Achar.