Two words, and you will be able to ride with no hands:

Lean Back

I have removed my jacket and rolled it up and put it in my jersey pocket with my hands off the handlebars, but that was only because there was a woman rider behind me, and I was showing off. I have decided I will never do anything like that, or anything that prevents me from quickly putting my hands back if necessary. Also, I don't do it if it is windy.

I view it as an important skill, because it lets me stretch my back/neck/shoulders. Also, if I'm tired, and a long gradual descent is coming up, I can just sit back and rest. It's just like taking a break on a bench, but the miles keep clicking off.