i've done this and that's how i've got konqueror set up right now to open with a blank page. let me see if i can remember how i did it....
in your location/address bar, type "about
:blank" and press the enter key.
on the konqueror File menu toolbar, click Settings > Save view profile "Web Browsing"
i think that's all you need to do. but like i said it was a long time ago when i set it up that way so my memory isn't good on this.
edit: you may have to do this.
do the about
:blank thing in your location bar
then go to Settings > Configure View Profiles
select Web Browsing from the list
check the box labeled Save URLs in Profile
click the ok button
click Settings > Save view profile "Web Browsing"
but i'm still not sure....