Prepare the discs for the gyozas: cut the dough into 4 pieces of the same size.
Flour the work surface with cornstarch or potato starch so that the dough does not stick. Leave the dough pieces under a damp cloth so that the dough does not dry out.
Take a first piece of dough and flatten it into a "sausage shape" of about 3.5 cm in diameter.
 Cut it into 3/4 cm squares.
 Take a square and roll it to form a ball, then flatten it with a rolling pin to obtain a circle of 8 cm in diameter (you can also use a cookie cutter to make a nice circle). Flour the starch discs so that they do not stick.
Once the discs are finished, garnish them with a spoon of filling in the center and leave 1.5 / 2 cm between the edges of the disc and the filling to be able to close them. To do this, soak the edges of the water with your finger, and fold either according to the rules of the art (look on the internet) or as you feel.
The gyozas are ready to cook! Pour a drizzle of sesame oil in a pan.
 Once the pan is heated, arrange the gyozas in a circular manner, the flat side in contact with the pan, and sear them over medium heat 3 min. The flat side should be golden brown.
Then pour about 100 ml of water into the pan and cover for 6 to 8 minutes.
Remove the lid and fry for another 3/4 minutes.
Finally, prepare the seasoning: mix the soy sauce and the rice vinegar. You can add sesame oil, sesame seeds, fresh grated ginger, chili, etc. to your taste.