I am not sure if I understand your question. If you need a "full screen view", that is available under the view menu. That gives you the entire screen for the browser window. To return to normal view use right click and full screen again.
If this is not what you need, please give more information.
OK, I understand now. KM has a zoom feature. It is the litte plus and minus symbols on the tool bar. ( I am using klassic skin ) The one with the minus symbol can reduce the page so that it fits the screen and the scroll bar across the bottom goes away. NOTE There are three ways to configure the zoom. You can zoon text only, images only, or full page. You want to select full page to get the effect that you are asking about. It may take more than one click to reduce to page to fit the window. I don't think KM has a one click to fit feature, but I will do some more research on this.