I was using OneNote on a multiple monitor machine the other day and noticed that by default, the application would always start on my primary monitor. Since I work back and forth between OneNote and Outlook all the time, I usually have one app on one monitor and the other on the other. I vary which one is on which, though. If I need to book meetings, a task which takes several minutes, I want Outlook on the primary monitor. It is just easier for me to see it there. Likewise, if I need to type a manifesto into OneNote, I want it on the primary monitor for the same reason.
With the desktop version of OneNote (my words, think "OneNote 2013 that runs on Windows 7 and Windows 8"), I can move it around and minimize it if needed. Apps from the Win8 store, though, take the full screen, can be minimized, but I am still learning how to work with them effectively. In my case, I wanted OneNote to be on the secondary monitor.
The "trick" I found uses Hot Corners - if you click in the corner of the screen, Windows 8 will do different things. For instance, clicking down in the bottom left near where the Start button used to be will open the new Start screen. Clicking in the upper left will switch you to the most recently used application.
So what I found was if I click in the top left of my secondary monitor, OneNote (or the app I used last) will open on that monitor. And it opens fairly quickly as well - good performance is always nice. Now I can easily switch which monitor holds which applications for me.
If you are using a desktop machine with Windows 8 and have multiple monitors, this little tip may help you out as well.
Questions, comments, concerns and criticisms always welcome,