Amazon's Kindle app for Windows 8 and RT was one of the first to reach the Windows Store, but it hasn't been very seamless for those purchasing more e-books from a touchscreen. An update today puts them on an equal plane: there's now an in-app Kindle Store for tablets and other devices where a mouse isn't a given. About the only other requirement is English. If that's no obstacle (and it likely isn't if you're reading this), shopping from a Surface should be much easier.
Microsoft Windows RT