If not already toasted, dry roast the peanuts in a skillet until gently brown and remove any shell. Place the peanuts, peanut butter, sugar and coconut oil in a food processor and blend until combined - it doesn't have to be smooth, you want a bit of texture.
Take rounded teaspoons of the peanut paste and spoon onto a parchment-lined plate or baking sheet in small mounds, roughly balls. Use all the mixture to make eight balls, as even as possible. Place the plate/baking sheet in the freezer for a couple minutes while you prepare the outer dough.
Mix the rice flour and hot water for the dough to make a smooth dough.
Divide the dough into eight equal pieces and roll into balls. Use some flour on your hands if it is very sticky.
Flatten one of the pieces into a circle either with a rolling pin or your hands. Place one of the chilled peanut filling pieces in the middle. I recommend keeping the remaining filling pieces in the freezer and just take out a couple at a time so they don't get too soft to work with.
Carefully bring up the sides of the dough to join together around the filling. Try not to have it doubled over but relatively even thickness on all sides. Once all joined, gently roll the dumpling in floured hands to form a ball. Repeat with the rest of the pieces of dough.
When ready to cook, bring a pan of water to a continuous boil and add the balls of dough. Cook for a few minutes until they rise to the top (like cooking gnocchi) then remove. You can serve them as they are, but commonly served in a light sugar syrup (see notes below) or warm water.