Check system settings for a keyboard entry / applet. I'm on LMDE Cinnamon and have no idea what the equivalents are on Kubuntu, but over here it's definitely possible to change/remove the default keyboard assignments and set up custom ones instead.
For example, I have Shift+WWW (the multimedia key that starts a web browser by default) set to start the browser with an alternate profile. I could just as easily set plain old WWW to, say, start a terminal instead, or run that custom command.
The hardest part is knowing what custom command to run to get the desired effect.