It's not easy, since the Q2A database currently only keeps track of when users last did a write action (like voting or posting), not when they last viewed a page.
So you would have to use an advanced theme to keep track of user page requests in a new database table, and then it could also output the results. The function qa_get_logged_in_userid() will be helpful - it returns the id of the currently logged in user, or null if nobody is logged in.
