It turns out this is quite easy and works fine:
And that's it. It will take couple of seconds but it loads ok. Also, killing krunner and restarting it from Konsole doesn't seems to be a problem. For those of you, which see something like 4GB for plasma-desktop and 2GB for krunner.
By the way, this seems to be the problem also with "kdesu firefox" not working (it returns a stub).