Arms too big? That's not exactly a common problem. Anyway, if your arms are developed, I doubt that they'll get much bigger by working them secondarily through presses, rows, and pullups. While many people here, myself included, advise that compound exercises will work your arms too, making isolations less necessary, what we mean is that many people base their entire workout on arm exercises and neglect everything else. Something tells me that you've been doing exactly that. If your back and chest are underdeveloped compared to your arms, start hitting the heavy compounds. I don't think you're arms will grow much more at this point by doing compounds because your back or chest will probably wear out before your arms do. Moral of the story - do heavy Bench Presses, Rows, Military Presses and Pullups
If you really want to isolate your chest, do flys. It's probably a good idea to do them in addition to bench presses.
Wide pullups do focus more on the lats (back muscle). Also, the type of grip you use will make a difference. An overhand grip (palms out) isolates the lats, a neutral grip (palms facing each other, using parallel bars) recruits the biceps some, an underhand grip (palms facing you) recruits the biceps even more.
BTW - When you say hand muscles - what are you referring to? Arms, forearms, your hands?