Tip the minced pork into a large bowl. In a separate small bowl mix together the cornflour and water to create a smooth liquid. Pour it over the pork.
Finely chop the ginger, garlic and chives. Add them, along with the soy sauce, rice wine vinegar, sesame oil and salt to the pork.
Using a wooden spoon, thoroughly mix the pork and seasonings until everything is fully combined and the mixture is smooth like a thick puree. It's perfectly fine if you do away with the wooden spoon and use your hands though, it'll probably just slow you down.
Set up everything you will need: a small bowl of water, your pork mixture with a tablespoon, a pile of gyoza wrappers, and a spare plate.
Lay a gyoza wrapper in your hand. Wet the circumference of the paper with a finger. Spoon a blob of meat into the centre and flatten it into a rough circle. Fold the wrapper in half so the edges are touching, but before they do, use your thumbs to fold pleats. Seal the edges tightly, then place the gyoza on the spare plate.
Repeat with more wrappers until you finish the pork.
Place a non-stick frying pan on medium-low heat, and add a drop of flavourless oil. Once hot, add as many gyozas as you want/can fit. Let them cook gently for up to 5 minutes, until the bottoms are golden brown.
With your pan lid ready, pour in 4 tbsp of water. It will immediately steam so quickly put the lid on. Leave them to cook for another 3-4 minutes. Remove the lid and the gyozas should have shrunken and the meat filling should be firm and heavy.
Let the water evaporate and gyozas steam dry for another minute or so. Remove from the pan and cook your remaining dumplings. Serve with soy sauce if you wish.