To force the first loaded page in your app, add this line in your config file (www/config.js) :
firstLoadedRoute: '/my-route/with/parameters',
To make a link that dial a number, use the tel: pseudo-protocol :
<a href="tel:XXXXXXXX" >Dial a number</a>
In order to make this link work, you must allow it on config.xml :
<access origin="tel:*" launch-external="yes" />
The process is the same for the mailto: pseudo-protocol
<access origin="mailto:*" launch-external="yes" />