We can delete pages from the Dot Wiki files even though the wiki server itself won't (yet) do this.
Other users may have links to a page that will fail without explanation when deleted. Consider simply replacing the page with a pointer to a preferable page.
Login and change directory to the desired site's pages subdirectory.
Check that the page in question is in fact not wanted.
Remove the page and coax wiki to rebuild the sitemap without it.
rm bad-page rm ../state/sitemap.json