In the current KDE you can use kstart for this (assuming the application you want to start is xosview):
kstart xosview -window xosview -sticky -decoration none |
In KDE-1.0 you'd need to write something like this in kwmrc:
[Sticky] stickyClasses=xosview, [Focus] noFocusClasses=xosview, [Decoration] noDecorationClasses=xosview, |
In the current KDE you can set these settings in the control center under Windows/Advanced.