The ability to edit sites is currently only available (like you said) through the admin UI- on the left side frame- the "Edit Sites" button under the header "Edit Functions" subcategory- then by choosing the Category which the site is listed under (if you can remember the Category that is - which I often can't seem to remember).
Not sure how to code the search function in php in order to point the search form function to query the MySQL table(s) containing the sites' title (or other searchable tables)?
Just not that able in PHP sorry-
I bet you could get the change implemented by Dewed if you offered to pay for it- Just kidding??