Here are a few keyboard (and mouse) shortcuts for Windows 8 when in Metro mode:
Application Search Win+Q
Settings Search Win+W
Files Search Win+F
Settings Charm Win+I
Rotation Lock Win+O
Time/date and start menu Win+C
Of course you can still use the old keyboard shortcuts such as Win+D or Win+R or Win+L.
If you’re using a mouse you can activate the charms/options by putting the mouse at the bottom left edge. Mouse mode also lets you active in-app options by right clicking.
You can use the keyboard’s arrow keys and page down/up to pick tiles. Use Enter to launch them. The menu button will let you select them.