"Gather windows" for all apps?

How do I move all apps from a Secondary Desktop that I can't see to my Primary Desktop that I can see? This is something that I end up faced with at least once a week and its incredibly frustrating.

This is a problem on any version of OSX without Spaces. Mavericks, Yosemite, and anything else lacking Spaces is a problem.

I am hooked to a Projector for a meeting and I can't see my Secondary Desktop.

I need to change settings, for example the background image needs to be changed, but I can't see the Secondary Desktop background controls and so I can't change anything.

In Windows there is an option to "Move" an open window using the arrow keys. You can recover -any- window that you can't see.

Is there anything like this in Yosemite?

I used to use Spaces for this but the new Mission Control is horrid and doesn't come close to what Spaces used to offer.

I need to "simply" move a window from my Secondary Desktop to my Primary Desktop without being able to see the Secondary Desktop...

This is a huge issue for me. I am left frustrate and wanting to throw my Mac into the river almost once a week because of this issue...

please someone help me!!