Finely grate 1 piece of ginger, then finely shred second piece.
Place cabbage in a bowl. Sprinkle with 1 tsp salt then leave for 30 minutes. Squeeze handfuls of cabbage to remove excess water then place in a bowl. Add 1 1/2 tsp grated ginger, minced pork, onions, sauces, sesame oil and wine and combine well.
Line a large tray with baking paper then dust with cornflour. Using a finger, wet edge of a wrapper with a little water. Place 2 level tsp of filling in centre. Fold wrapper in half and, using your thumb and index finger, pleat one edge, then press edges together to seal. Place in a single layer on prepared tray. Repeat with remaining wrappers and filling. Dumplings can be made up to 6 hours in advance and stored covered in the fridge.
Preheat oven to 150°C Heat 1 tbs peanut oil in a non-stick frying pan over medium-high heat. Add 12 dumplings, pleated side up in a single layer, and cook for 1-2 minutes or until brown underneath. Carefully add 1/2 cup boiling water, then cover partially with a lid and cook for a further 4-5 minutes or until water has evaporated and dumplings are crisp underneath. Transfer to an oven tray, cover with foil and keep warm in oven. Repeat with remaining oil and dumplings.
Serve with bowls of red vinegar combined with the shredded ginger, for dipping.