Here's how many people will end up viewing multiple Windows 8 metro apps in fullscreen at the same time: they'll enter Windows 8 desktop mode (i.e., the not-metro interface); they'll open up two separate Remote Desktop (RDT) sessions to their own computer, probably one or both on their second screen (and perhaps in scaled mode so the RDT full screen doesn't actually take up the full screen); they'll take their RDT sessions, each initially displaying the Metro "start" screen, and open up one Metro app in each RDT session. Problem solved.