In a bowl (I use a souffle-size bowl, around 2 cups) stir together the rice flour and sugar.
While mixing with a spoon or small stiff spatula, pour in the boiling water.
Stir in clockwise direction until the lumps disappear, and the batter is slightly elasticky, about 2 minutes (note: it will become difficult to stir, but try your best anyway!).
Cover the container with plastic wrap, and microwave on HIGH for 2-4 minutes, depending on your microwave.
Meanwhile, grease a ziploc bag well.
Invert the bag (oil side out), and remove the mochi from the bowl into the bag (you can let it cool a bit before you do this, but the more you cool it, the harder the bowl will become to clean =/). Don't burn yourself!
While the mochi is still warm, start kneading. To knead: Stretch and flatten the dough inside the bag with the palm of your hand, then pick up the bag at one corner, shake it so that it rolls into a ball again, then repeat. You can also knead it by placing the mochi into a greased bowl, and knead it as you would a normal dough. Knead for about 7~10 minutes, or to the consistency (chewiness) you want.
To prepare the coating: Process the peanuts in a blender or food processor, and spread the powder out in a plate. Do not add sugar to the coating! Because the sugar will dissolve with the moisture in the mochi, making it super sticky.
Pull off a teaspoonful-sized mochi ball with your hand, and coat in peanut powder. Alternatively, if you prepared it inside a bag, cut off a 1/4" corner, and squeeze from the bag. Separate the balls with greased scissors, or with chopsticks =P.
Variations: Instead of using a coating, you could also wrap sweet red bean paste inside the mochi for daifukus =).