From reading this page it looks like you can use smaller monitors and there are a number of ways of getting it working:
http://www.clickonf5.org/14830/windows-8-metro-style-apps-running-on-low-screen-resolution-netbooks/
One way is to attach another monitor.
Another is to enable DownScaling, restart, then increase the resolution:
Locate the following location in Registry window,
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4D36E
968-E325-11CE-BFC1-08002BE10318}\0000
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4D36E
968-E325-11CE-BFC1-08002BE10318}\0001
In both of these locations, find
“Display1_DownScalingSupported” in the DWORD list
Right-click on the
DWORD and select modify, change the value from 0 to 1 for that DWORD