How do I keep rice based noodles from sticking together?
I have only experience with pho noodles. I don't know if the pasta you are referring to behaves fundamentally different to the noodles that I'm familiar with. The ingredients seem to be almost the same: rice flour. Some kinds of rice pasta are made with brown rice flour but this is basically white rice flour with the bran layer and the germ. I guess rice starch in pasta and pho noodles should behave quite similar. 

Regarding the pho noodles which are also very prone to sticking to a noodley blob you have two options:


Soak the rice noodles for about one hour (I don't know the exact time) in (luke)warm water until the noodles are soft. They will not be as soft / chewy as cooked but rather can be bent to a certain extent until they break. When soft, remove the noodles from the water (optional: and store them in a closed container in a cool place until you need the noodles). Reheat your sauce and put the desired amount of noodles in the same pan. The noodles will cook very quickly. Instead of this you can sautée the noodles first and then add the sauce (very tricky, I always end with a ball of noodles; my parents do better). It is almost rather reheating the noodles than cooking.
Cook the noodles and rinse them thoroughly (!) to remove the starch. (Sometimes the noodles did stick after rinsing. Then oiling helps.)