How do I uninstall this application
How do I unistall Desktop Remote client? and how can I delte old Icloud user names
MacBook Air, iOS 7.1.1
For what reason do you think you need to uninstall the client? If it's not active, it's completely harmless, and uninstalling may cause unexpected issues, though admittedly that's unlikely. And it will probably just be reinstalled when next you upgrade OS X.
As to old iCloud names, from where are you trying to remove them?
Regards