rdesktop

For this to work, the remote windows machine must allow remote desktop connection:

Go to "Control Panel"
Click on "System"
Click on "Remote" tab
Check the "Allow users to connect remotely to this computer" box

On your local Linux machine, download and install rdesktop.

Launch rdesktop:

rdesktop -u username -d genius.local -f remote-host-ip

How can I switch between my remote windows machine and my local linux desktop manager?

Ctrl+Alt+Enter

How can I disconnect from my remote desktop?

Click on the Start menu.
Click on Disconnect.  The Disconnect button is at the lower right hand of the start menu where the "Shutdown" button normally is.

You can disconnect your remote desktop. Your programs will continue to run, and later you can reconnect to previously disconnected session, continue to control your programs. Keep in mind that there may be a limit on how long your session is open, perhaps 3 hours. If you disconnect your session, and don't reconnect within 3 hours, your remote machine may shut down your programs, and log you off.