There is no method within Q2A so it would be a good idea for a plugin.
But you can find it direct in the database. If you use something like phpMyAdmin you can run a query like this:
SELECT u.handle, v.vote, v.flag
FROM qa_posts p, qa_uservotes v, qa_users u
WHERE v.postid=p.postid AND v.userid=u.userid
Replace 0000 with the actual post ID that you want (the one in the URL). You could also add things like AND v.vote=-1 to find downvotes, or v.flag=1 to find flags.