I wanted to open some photos today (to add to my blog) on my Windows 8 workstation, and it kept opening the full-screen metro app instead of the normal picture viewer. It really annoyed me, and I looked for a quick and dirty way to remove ALL metro apps. This one-liner I wrote quickly removes all metro apps that can be removed. I know I liked it!
Get-AppxPackage | Remove-AppxPackage -ErrorAction SilentlyContinue