Do you have to use Orion to use Leapmotion and do yu have to mount Leap motion?

I'm not creating a VR system from scratch. I'm using a VR system i bought at the unity store. It works with Leap motion and it was even made and used before Orion software came into the picture and it worked.

Do i have to install Orion software even if i'm not developing the VR software myself from scratch?

And secondly can leap motion work for oculus rift VR games,  even if i don't attach it to the Oculus Rift? Can i just put it on my desk?