Can I make grain-free noodle/ravioli/dumpling dough?
You could look into cellophane noodles. They're made from starch (often yam or potato), so it sounds like they'd work for you.

If you have a decent Asian grocery store around, you may well be able to just buy them, too. You'll just have to be careful to check the ingredients, as they are sometimes made with corn starch too. (I'm not sure if it's whole corn or even the starch that you can't have.)