One way to do this is by typying uninstall in the search textfield on the K Menu. The following then appears as the only result,
Click this link and a window appears similar to the add/remove programms that you see on the windows platform. Select the program to uninstall and remove it.
Alternatively, you can simply type uninstaller on the Konsole and the same window appears.
Note that for certain programs, a system restart may be necessary.