Is there any need to delete the super admin account? If you just have lost the password then you can change it with SQL as explained here: http://www.question2answer.org/qa/30100
If you still want to delete it then it is always better to use higher level Q2A functions than using plain SQL as they take care of things that just one DELETE statement won't (e.g., what happens with posts of that user, votes, etc). I'd recommend just running this:
$userid = 1; // Here goes your super user database id. Most likely, it'll be 1
require_once QA_INCLUDE_DIR . 'app/users-edit.php';
qa_delete_user($userid);
