Windows 8 includes two fantastic features for people using multiple monitors. The first feature lets you choose which background image to have on which monitor, so you don’t have to have the same background on all monitors. The second feature is an easy keyboard combination which lets you move any Windows Store App to another monitor.
To change your desktop background images independently, go to the charms bar (lower right-hand corner of the screen) and click on Settings. Next, click Personalization. From the personalization menu, select Desktop Background, and you can right-click on any image and select set for all monitors, set for monitor 1, or set for monitor 2.
To switch a Windows Store App from one monitor to the other, simply open the App and hold down the Windows Key (next to the Ctrl key) and press Page Up to move the app to your monitor on the left. Press Page Down to move your app to your monitor on the right.