idk if this is waht its called.. im talking about the rubber padding on the chain side of the swingarm, close to the frame.  i noticed that my chain slides/touches this rubber thing.  is that normal?

Chain slider, and yup!  Replaceable for a reason.

ok good. i didnt really think much of it until i looked at my friends kawi and saw his didnt touch..  btw what is its purpose.   ok i know its to protect the swingarm, but why is it designed that the chain has to rub on it?

For when you sit on the bike, and are riding it, and the swingarm goes through its arc of motion. When the suspension is compressed, the swingarm forms a straighter line between the front and back sprocket centers and the swingarm pivot, taking up whatever slack you had in the chain (that's why the slack is there) and "lifts" the chain clear of said chain slider.