This is a good one I do, it came from an old saying my mother used to say that goes "cold hands; warm heart."
You: "Do you have cold hands?" *grab her hands gently*
Her: "I don't know... Why?"
You: *strong eye contact* "They say if you have cold hands you have a warm heart, I just wanted to find out how coldhearted you are haha

"
Flirt with her depending on whether she has cold or warm hands, if her hands are warm, you can be let go of her hands suddenly and be like "Jeez! You must be the ice queen!" or something.
It's a bit lame, but it works if done in a playful manner. Don't go word for word, be in the moment and have fun with it, strong eye contact. It's ON if she holds your hand back!
The main point of it, is it is a good starting point if you haven't kino'd her at all yet and you're a bit nervous about doing it.