Put a large pot on the stove with a couple inches of water in it. Add a rack that'll keep your dumpling cups out of the water.
While that's heating, mix together the ground pork, ginger, garlic, and sliced green onion. Divide it into 6 equally sized portions.
In a small bowl, mix together the soy sauce, black vinegar, sesame oil, and chicken stock. Set aside.
In a ramekin or wide-bottomed coffee cup, add one dumpling wrapper.
Spread one of the meat portions over the wrapper with a spoon.
Add a teaspoon of the chicken stock mixture on top of the meat.
Continue layering in this manner until all of the ingredients are used. You should have 3 layers of meat in each cup, and 4 wrappers in each cup.
Place the ramekins onto the steaming rack and cover tightly with a lid.
Steam the dumplings for 15 minutes, or until the internal temperature reaches at least 165°F.
Carefully remove from the pot and let cool for a few minutes before you dig in. Top with some chili crunch if you like it spicy, or drizzle on some more dumpling sauce or sriracha.
