River wants to delve into Luke's mind and find out all about him, a natural curiosity paired with an enhanced talent that satiates curiosity all too easily. But she's cautious too, and she knows it probably isn't a good idea to go poking around in heads that can poke back. So she sticks to the surface, open to reading thoughts and intentions that he projects, but going no deeper. If she wants more, she'll have to settle for old fashioned conversation.

"Who are you?" Seems a good place to start.