Stuffed Dumpling Made with Rice Flour
Use boiling hot water to gelatinize the  starch in the rice. 

Instead of a cup of room-temperature water, use boiling water to mix with the rice flour. It will make the dough stretchable. You might need some more rice flour to use as coating to prevent sticking. This link of a recipe describes it best : http://kitchentigress.blogspot.sg/2011/09/how-to-make-soon-kueh.html

Note:

I added more information as requested by Doug.