Hi there, you can get some information about your visitors in a few ways.
You can check your site statistics and see things like views by country, search-engine terms, referrers, and more:
https://wordpress.com/#!/my-stats/
Here's a guide to interpreting your statistics:
http://en.support.wordpress.com/stats/
If you choose to allow likes and comments on your posts, you can click on their usernames or Gravatars to see their profiles or blogs.
It is not possible to see a complete list of your actual site visitors, for both privacy and technical reasons.
Hope this helps!