1, In a bowl, whisk together the rice flour and 3½ cups water until smooth. Cover and allow to ferment at room temperature for 4 days.
2, Carefully pour out 1½ cups water from the settled rice flour. Add ¼ cup fresh water to the batter and stir until smooth.
3, Bring a large stockpot of salted water to a boil over high heat. Keep the water hot while you prepare the dough.
4, In a heavy-bottomed 4- to 6-quart pot, heat the oil over high heat. When the oil is hot, add the batter and turn down the heat to low. This is a two-person job: one person needs to stabilize the pot while the other one quickly and firmly stirs the batter with a wooden spoon. The dough will begin to thicken. Continue cooking, stirring continuously, for 5 to 8 minutes, until the dough is a thick, firm paste. If any dough sticks to the sides of the pot, do not scrape it off.
5, Transfer the dough to a stand mixer fitted with the dough hook and add tapioca starch. Mix on medium speed for about 10 minutes, until it forms a sticky ball.
6, Bring the water back to a boil, then adjust the heat to keep it at a vigorous simmer. While the water is heating, dust a clean work surface with flour, transfer the dough to it, and knead for another 5 minutes, until smooth. Cover the dough with plastic wrap to prevent it from drying out.
7, Prepare a large ice-water bath and place it near the stove. Put 1½ cups of the dough into a potato ricer, keeping the remaining dough covered. Position the ricer directly above the center of the pot of boiling water and press firmly to extrude the noodles. As you press, smoothly lower the ricer close to the water and shake it gently from side to side to break the ends of the noodles free, allowing the noodles to fall into the simmering water. Simmer the noodles for 1½ to 2 minutes, until they bunch up to one side of the pot. With a spider or tongs, carefully transfer the noodles to the ice-water bath. Once cool, transfer to a colander and let drain. Repeat with the remaining dough, replacing the ice water as needed. When all the noodles have been cooked and cooled, rinse the noodles under cold running water to remove excess starch. Drain the noodles. The noodles are best used the same day they are made, but they can be covered and refrigerated for up to 1 day.