Does anybody know a FileChooser control that can be used in Microsoft Surface?
This is probably not the answer you want, but I would recommend you re-think your use case a bit to make the file choosing a bit more user friendly.
For example, it is highly unlikely that your users need to choose an arbitrary file from the surface device's file system. You probably have a defined folder where they can load documents (or whatever) from. What I would do is to is to build your own view that loads these documents into a touch friendly surface (a list, a librarybar or something) where the user can select the document to load.
As an example, if you have a photo application and you want the user to chose a folder to load pictures from then the design could be that the app displays the folders as "galleries" or "albums" which the user can click on. In the background, they could map to folders on the surface harddrive but that's not of interest to the user.
You should think of the surface as an embedded, special purpose device, and exposing the internals (file system in this case) is IMHO not a good idea.