Roughly chop the cabbage, onion, carrot, scallion, and ginger. Place them in a food processor and pulse for about 20 seconds until finely chopped but still slightly textured. Transfer to a large bowl.
Add the chicken to the food processor and pulse for 15–20 seconds until minced but still slightly textured. Add the chicken to the bowl with the vegetables.
Add all the marinade ingredients to the bowl and mix well until fully combined.
To assemble the dumplings, hold a wrapper in one hand and place about a heaped teaspoon of filling in the centre. Lightly wet the edges of the wrapper with water.
Fold the wrapper in half and pinch the centre closed. Create small pleats on each side to seal the dumpling tightly, making sure it has a flat base.
Heat oil in a non-stick pan over medium heat. Place the dumplings flat side down and fry for 1–2 minutes until the base is lightly golden.
Add water to the pan so it reaches about one third of the height of the dumplings. Cover with a lid and steam for 4–5 minutes until cooked through.
Remove the lid during the last minute if needed to allow the remaining water to evaporate and the dumpling bases to crisp slightly.
Mix the soy sauce, vinegar, and sesame oil together in a small bowl to make the dipping sauce. Serve with the hot dumplings.