I am using openSUSE Leap 42.1 (64-bit) with the KDE desktop environment.
Where in the Application Menu do I go if I want to change the screen saver theme? I’d like to see what else I can choose beside a blank screen when 10 minutes of inactivity pass…
Settings (or Favorites)->Configure Desktop->Workspace Behavior->Screen Locker.
But you can only set the screen locker theme and background there. Plasma5 does not support screen savers any more.
(if should be possible to run xscreensavers though, if you want animations on your screen after some period of inactivity)
If you want to you can use the xscreensaver like wolfi said using instructions from here: