The Star Wars well from which to mine new nuggets may in fact be bottomless. And this one is as delightful as any. Imagine looking back on a picture you drew as a toddler. That’s sort of like what Mark Hamill’s experiencing as he watches his original audition for the role of Luke Skywalker. In promoting N.A.I., an organization that helps prepare underprivileged students for college, the self-deprecating Hamill reluctantly sat down to be embarrassed as he viewed his 1976 tape. It’s fascinating to watch him cringe not only at the sound of George …