In a small mixing bowl combine the pork, green onions, ginger, garlic, cornstarch and soy and mix thoroughly. Working in batches, lay the gyoza wrappers on a clean, dry surface and place about 1 tablespoon in the center of each wrapper. Moisten the edges with water, and bring the edges together at the top so that they meet. Press to seal. Place formed dumplings on a parchment-lined baking sheet and cover loosely with a damp paper towel while you form the remaining dumplings.

Make the sauce by combining all ingredients and set aside.

In a large nonstick skillet over low heat, add the vegetable oil and, when hot, add the dumplings and cook until golden brown on the bottom, 1 to 2 minutes. Add the chicken stock, reduce the heat to low, and cover the skillet. Cook the dumplings until wrappers are tender and filling is cooked through, 3 to 5 minutes. You may need to add a bit of additional stock or water if the liquid has evaporated before the dumplings have finished cooking.

Serve the dumplings hot with the dipping sauce.