Some articles on kdesu:

Comparison Of Privilege Authorization Features - Usability Considerations - Saving Credentials
... sudo, gksudo, and kdesu do not ask the user to re-enter their password every time it is called to elevate a program ... or all programs not running in a terminal (for gksudo and kdesu) prefixed by either of those commands before the timeout receive administrator privileges ... The equivalent command for kdesu is kdesu -s ...