Julie, Corian sands easily but ... it makes a ton of baby powder fine dust. So wear a mask. Also you have to use more fine sandpaper than you would with wood. For instance in most cases 220 would be acceptable for wood. Not in Corian. Since Corian is a plastic and a lot of the finishes we have will not stick well to plastics you will need to use sandpaper with very high grit number perhaps as high as 6000 to get that showroom finish we demand on our projects. And yes they make 6000 grit and higher normally for working on plastic windows and things like that.
DW