Some types of potato have a higher water content which means they're not so good for frying. You'll have to do a bit of research to find out which ones though.
All potatoes do have water though, so a good idea is to grate them onto paper towels to soak some of that up. You could also then put them in the fridge to further dehydrate them.
As to making hash browns, I haven't really got a clue.
