How can I make my arms thinner?

[KaraMullin]

I'm pretty skinny, and I don't have a problem with my stomach or thighs or anything. But I'm kind of insecure about my arms, how can I make them thinner? They aren't fat or anything, but they're kind of muscular and wide looking and I just want to make them look better. i'm self concious about wearing tank tops because they look kind of gross and my arm fat likes hangs over :|

so any workouts or something I can do to make them thinner?
thanks