We have a list of almost 80 attached files on a particular K2 page. When I originally uploaded them, I didn't name so they're understandable to our visitors. I went to the attachments tab to change the file names, but the only options I see are "Download" and "Delete." Is there a way to change the file names somewhere else?

There isnt any direct edit link trough K2.
You could change names deleting and uploading again all files, or editing the #_k2_attachments table trough PhpMyAdmin.