Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.
Wash the sweet potato and prick it a few times using a thin knife. Place on the baking sheet and roast for about 45 minutes, or until the flesh is tender. Remove from the oven, cut the sweet potato in half lengthwise, and let it cool completely.
Scoop out the flesh and transfer to a mixing bowl. Add ½ cup of the rice flour, potato starch, and salt. Using a wooden spoon, mix to combine. At this point, the dough should be very sticky, add one tablespoon of rice flour at a time and mix to incorporate. I ended up using a total of ¾ cup rice flour. The dough should be soft and just very slightly sticky.
Cover the dough with plastic film and let it rest at room temperature for about 30 minutes.
Divide the dough into 4 balls. Roll each ball into a long 1-inch thick log. Cut each log into 16 bite-size pieces. I recommend rolling the dough on a smooth countertop, or a cutting board lined with plastic film to prevent the dough from sticking.
To shape the gnocchi, take one piece of dough and roll it into a ball. Place it in the palm of your hand and use a fork to create some indentations by slightly sliding the tines on the dough. Do not press too much. Place on a cutting board and repeat with the remaining balls of dough.
Bring a large pot of water to a boil. Once boiling, carefully drop half of the gnocchi into the boiling water and cook until they float, 2-3 minutes. Use a slotted spoon to remove the gnocchi from the water and transfer to a plate. Repeat with the remaining gnocchi.