The uncooked dumplings can be frozen for up to 1 month. Do not thaw before steaming or pan-frying.
Gyoza wrappers, sometimes called pot sticker wrappers, are round and slightly thinner than wonton wrappers. They're available in the refrigerator case at Asian markets and some grocery stores.
You can easily freeze dumplings: Spread the uncooked dumplings on a parchment-lined baking sheet, cover the sheet with plastic wrap and freeze until the dumplings are firm, at least 4 hours. Store the frozen dumplings in sturdy freezer bags. Steam or pan-fry the dumplings per the recipe, but increase the cooking time by a few minutes. For the pan-fried version, add more water if the pan dries out before the dumplings cook through.
Soy sauce mixed with rice vinegar.