Windows 8 apps are meant to be run from the Windows 8 Start screen and in full-screen mode. You can snap them to the side of the Start screen, but they're still limited to the Start screen. If you're simultaneously using desktop programs and apps, you'll have to toggle between your desktop and Start screen to use them. This inefficient back and forth can be alleviated with the use of a program called ModernMix. ModernMix, just released by StarDock as a public beta, aims to give Windows 8 users the flexibility to run Windows 8 apps right on the desktop.
To get ModernMix, go to StarDock's Web site and request the download link by e-mail. Once you've downloaded and installed ModernMix, you'll see the configuration window. To launch Windows 8 apps as windowed apps on the desktop, choose the right-most option. You can also choose the middle option, which launches the app in a maximized window on the desktop.
The next time you launch a Windows 8 app, it'll appear on the desktop like any other Windows program. You can also toggle modes by clicking on the icon in the upper right-hand corner of the app window, or by using the F10 hot key.
Keep in mind that ModernMix is still in beta and will cost $4.99 to use after the 30-day trial expires.