Im writting a plugin who makes dynamic pages with simple page template:
the url is rewriting so internally call to http://domain.com/index.php?pagename=users
and works, but the problem is, how I can index it to make searches?
Do you have at least have a link to the query url somewhere on your public pages ?
Google does follow query parameters, so that will at least bring it to the crawlers attention.
(I almost have the opposite with my event/calendar plugin. google is paying almost too much attention to the pages and their date query parameters (moving forward in time etc). See notes on that here http://icalevents.com/4046-google-indexing-bandwidth-and-calendar-parameters/ )
Other good seo stuff will then help. Sitemaps etc
Also see if you can improve the markup on the page - if about people, then maybe some people microdata will help google index the page .(my plugin's html does event rich snippets) see Rich snippets - People: