Asian dumplings, or gyoza, consist of a meat filling inside a thin dough wrapper that is pan- or deep-fried. You can buy gyoza wrappers or skins at markets, but they are pricey and full of preservatives. Like pasta, homemade gyoza skins taste fresher than commercial varieties. For a truly homemade batch of gyoza, make your own skins or wrappers rather than purchasing them.
Remove the boiling water from the heat to cool to just below the boiling temperature, about 2 minutes.
Sift together the flour and salt in a large mixing bowl.
Stir the hot water into the flour with a fork until the mixture forms itself into a ball.
Cover the bowl with a dish towel and let rest for 1 hour.
Transfer the dough to a lightly floured surface and flatten it with your hands. Fold the dough over onto itself and turn. Repeat flattening, folding and turning the dough for 5 minutes to knead it to a smooth, elastic texture that bounces back when pressed.
Place the dough back into the mixing bowl and cover with the towel for another 30 minutes to rest.
Cut the dough into four equal pieces. Set three of the parts back in the bowl, covered with the towel to keep them from drying out.
Roll the dough into a sheet as thin as possible, 1.5 to 3 mm (1/8 to 1/16 inch) thick.
Press the cookie cutter into the dough to cut eight to 10 gyoza skins out of the dough sheet.
Dust these gyoza skins lightly with flour and set aside until ready to fill and cook.
Repeat rolling and cutting out skins from the remaining dough to have 30 to 40 gyoza skins.
Wrap extra wrappers in wax paper and seal in a zip-top bag to store in the freezer for up to one month.