I'd like to give users the ability to view their own profile. What's the easiest way to do this? I did not see a K2 user profile link at a menu item in J! 2.5.6.

Hi. You can do this with the following ways:

1. Making a menu link to "Users Manager"->"User Profile". K2 will detect this and extend the form with it's fields.
2. Use the K2 User module. When a user signs in he will get a link to his profile.