Open a PDF at a specific pageTag(s): Misc Prog HowTo
Use a URL like this
http://www.rgagnon.com/examples/realhowto-vbs.pdf#page=5
to open the specified pdf at page 5.
This document from Adobe describes parameters that allow you to open a PDF file using a URL or command that specifies both the file to be opened plus actions to be performed once the file is opened.