Grate the fresh wasabi into the cream cheese with the salt and mix. If you can't get hold of fresh wasabi, use wasabi from a tube (available at most supermarkets)
Lay out one of the gyoza skins from the pack. Have a small bowl of water at the side.
Put a small ball of the cream cheese/wasabi mix into the centre of the gyoza.
Wet the edges of the skin with water.
Working quickly, fold over one side, pleating it into 4 pleats, to join the other half. You should have a crescent shape.
Add groundnut oil to a wide frying pan and heat to a medium temperature.
Place the gyoza crescents onto the pan, not touching each other, until there is no more room. You may have to repeat this process 2 or 3 times or until the pack is used up.
Fry until golden on the underside, then add a splash or two of boiling water (from the kettle if you wish) and put a lid over the pan. (If you don't have a lid, you can use a sheet of tin foil).
Continue to fry for 3 to 5 minutes. Uncover the pan and serve the gyoza hot with the dipping sauce.