Check out these KDE keyboard shortcuts, because we all know we love shortcuts!
1. Alt-F2
This brings up the the “Run Command” prompt and gives you quick access to all your Linux applications. This is similar to Windows’ Launchy and GNOME-Do.

2. Alt-Tab
Cycle through the applications/windows you have open.

3. Alt-F4
Close the window you have in the foreground (i.e., the active window).

4. Alt-Esc or Control-Esc
Shows the KDE session manager, from which you can switch to a specific application or log out of KDE.

5. Ctrl-F[1..8]
Switch to a specific desktop.