Add the ground chicken, ginger, garlic, chives, soy sauce, sesame oil, rice wine vinegar, sugar and black pepper to a large bowl. Stir with chopsticks in one direction until the mixture turns sticky and paste-like and smells aromatic.
Lay a wrapper on a clean surface (or 6 at a time). Dip a finger in a small bowl of water and run it along one half of the wrapper's edge. Add ½ tablespoon of filling to the center. This may vary depending on the dumpling wrapper or your pleating confidence - add more if you're a bit more confident with your skills!!
Fold the wrapper in half over the filling and pinch the top center together.
For the easy fold, make one pleat on each side toward the center and press to seal (see image further up the blog for reference)
For the classic pleat, fold the right-hand edge in toward the center 3 times, pressing as you go, then repeat on the left and seal (see image further up the blog for reference)
Repeat with the remaining wrappers.
Keep the folded potstickers and unused wrappers under a damp kitchen towel or paper towel until ready to cook.
Heat the vegetable oil in a large nonstick skillet with a lid over medium heat. Add the potstickers flat side down and fry for 3 minutes, until golden brown underneath - you can lift them up to check. Cook in two batches if they don't fit in one layer.
Carefully pour in the water (it will spit so make sure to pour it from a jug rather than a small spoon), cover and reduce the heat slightly. Steam for 4 minutes, then remove the lid and cook for 1 more minute to crisp the bottoms. If the dumplings are sticking to the pan, just let the water evaporate and the base of the dumplings dry out and get crispy, then loosen the base with a metal teaspoon. Don't overcook steaming the dumplings though, or the filling will dry out.
Meanwhile, mix the dipping sauce ingredients in a small bowl, starting with 1 tablespoon water and adding more to taste.
Plate the potstickers, top with black sesame seeds and chives if using, and serve with the dipping sauce. Enjoy!!