It is possible to span Kodiak accross multiple windows.
The best way to do this is to choose the New Window icon 
in the main toolbar.
New windows will be secondary windows and closing them will not close the application. You will be presented with a window which warns you are about to close a secondary window.
They also contain a subset of the menu functionality, namely they do not contain toolbar items to create new items such as Client Orders, Market Orders etc.