1. Add flour, salt and rice flour into a large bowl and stir well. Add hot water and stir with a rubber spatula. Then knead the dough by hand for about 1 to 2 minutes until it gets smooth. You can shape it into a ball.
2. Let the dough sit in the bowl for about 15 min, covered with a damp cloth.
3. Remove the bowl of your stand mixer and attach the pasta roller to it.
4. Take some of the dough (about 1/3), shape into an oval. Flatten it and dust it with flour on both sides.
5. Feed the dough through the pasta roller (setting 1 - thickest), at least 3 to 5 times or until the dough is smooth. Turn dial to the thickness setting 3 or 4 and run the dough through once or twice. Repeat (once or twice) at each following position until you reach setting 8. The target thickness really depends on your own preference. I like thin skin, so I roll it until setting 8 :)
6. Lay the rolled out sheet of dough on a cutting board and cut it out, using a circle cookie cutter (8~9cm diameter suggested). Dust the cut out wrappers with katakuriko/potato starch and set aside. Repeat as many times as you can.
Gather all the scrap dough, put it all together and re-roll it a few times until it becomes thin layers again.