How do I get Windows 8 to run 2 Metro apps on each display of an extended display?

I have a Dell U2312HM 23" screen connected to my HP Envy laptop in Extended desktop mode. Is there a way I get 2 Metro "Windows 8 Style UI" to run side-by-side, with one app on each of the screens?

My attempts to run them both on either side have been futile, Windows insists on putting the other screen to desktop mode the moment I launch a second Metro "Windows 8 Style UI" app and this behavior is driving me nuts

I do not believe this is possible. While, starting in the Release Preview, you could move apps that run in the interface formerly nicknamed Metro, from monitor to monitor, Windows 8 still, by design as I understand it will only run that interface in one monitor and all other monitors will default to desktop mode.

While a reading of the Building Windows 8 blog seems to hint at how you can use these apps on any monitor, you will notice that in all of the examples shown, the interface formerly known as Metro only ever shows up on one monitor and the other(s) all show desktop mode.

Paul Thurrott has an article which elaborates on this a little bit more.

Note: Microsoft has announced that Windows 8.1 will have the ability to run Metro apps on multiple screens at once. Windows 8.1 will be a free upgrade to Windows 8, and is planned for release this fall.

The answer to this question is 'what you want is not possible in Windows 8 RTM'.

Using Windows 8 RTM, it is not possible to use two Apps side by side with this exception:

Two apps can be launched if one of the apps is in Metro-Snap mode. You can see this by opening a metro app, dragging the app by its top border to the left or right side of the screen. After this is snapped (we call this metro-snapped), you can hit the lower-left hotcorner on the monitor, open the start screen again (or just press Control+Escape). you now see the start screen, and you can launch another metro app. After this you will have two apps, one snapped small, and one snapped large.

We recently released RetroUI Pro v3 (RetroUI.com), which users the ability to run Apps in resizable windows. We have also integrated support for running multiple monitors using Windows 8. So you can run apps and move them between monitors in resizable windows. With that said, what this user has requested is not possible due to the architecture of Windows 8 RTM.

In RetroUI Pro v3, we released new technology called SuperSize, which allows a Metro app to be spanned across an array which is made up of of multiple-monitors.

Not attempting to hijack this topic, but thought I would shed a bit of light on the topic because I think we understand it pretty well.

To view a demonstration of our SuperSize technology: https://www.youtube.com/watch?v=ldaycb3RUOI
Technical information on SuperSize (Whitepaper)