As smu pointed out, there is a way to do this with latex. Another way that I sometimes use is "print to browser" and then from the browser print to file.
Admitted both are a bit more work, so well consider this request to mean direct export to PDF without dependency on latex.
I'd like to add my vote for this feature as well. It would be very helpful to be able to generate a wiki as a linked PDF, with a table of contents showing the page hierarchy and links to each (sub)page. If this could be done via the zim command line interface, it could be easily scripted and put in a cron job, which would be a great help for keeping an up-to-date, printable + ebook formatted version of the wiki always available. It would be very nice to be able to specify a custom page size & formatting features (e.g. font face, size, line spacing, page margins, header/footer, etc.) as well, especially where ereader devices are the intended output, rather than print.
What would be the best way to help bring this feature about? Do you envision this being in Zim core or as an export template?
I also give this request a thumbs up. I was searching an alternative to OneNote that runs on Linux and Windows. I'd like to use it for creating manuals. An export to PDF function wpuld allow to easy share a single manual without having the need of extra tools and knowledge to use them.
this options exists already: export to latex and compile the document to
a PDF.