A colleague recently asked a similar question ( How to start a MetroApp directly in Snapped mode? ), but this question is not a duplicate...
Programmatically forcing a Windows Store app to open in snapped view does not seem to be possible – by design. But can you do this or something similar on a Windows Embedded 8 machine? Similar things could include:
What we are trying to achieve:
The user logs in (on a preconfigured machine, assembled by us, possibly running Windows Embedded 8), starts our app and a snapped communication app (e.g. Skype or Lync) is (A) automatically there alongside our app, or (B) can be opened by pushing a button in our app.
Developers have the API necessary to take their app from SnapView to Fill or FullView. This is usually a less-advertised API because it could easily be abused. To that end, the reverse is not available. There is no API to move to SnapView.
I might also caution you, that unless you are sure of the device resolution, starting in SnapView (which is not possible as it is) would be a dangerously unreliable step as many (most?) displays do not support it (too small). And since you are talking embedded, I imagine this might be exaggeratedly so. Since it sounds like you might know the hardware, you can take that as a general rule, not for your circumstance.