1) To add a new dashboard, you click the content link  on the very first
dashboard. Then click create a sub dashboard, choose a name, position etc.

2)We don't use sharepoint for documents  here so I havn't done any work in
that area, but I'm sure someone else here can point  you in the right
direction there...

In order to place a send  link next to the document
you will need to modify the xsl files
that are used to display the document lists in the
Documnet Library dashboard,Categories Dashboard and
search dashboard.

on click of the document you can call you page(ASP)
that will do the task of sending the required mail
this page needs to be placed in the resources folder