Fox, I'd say if you are using a stock silencer and stock size rear tire and its still hitting the silencer, then you have something major screwed up with your bike. Kawasaki isn't going to let a bike with a defect like that get out to the public.
Anyway, The tab I'm talking about is this, and I can't make my explanation more simple than this. When you mount the silencer on the bike, you slide it on to the pipe end and then bolt it to the bike. The tab I'm talking about is the piece of metal on the silencer you put the bolt through. Simple as that..
Do U get me?