The Cordova plugin you mention is actually a "core" plugin that is included with Cordova. You may need to toggle it on in the AppBuilder plugin property pages to use it.
You can handle this today with just HTML (i.e. <a href="tel:18888888">tel:18888888</a>). On Android you may have to make a change to your config.xml: http://stackoverflow.com/questions/26432413/tel-link-android-not-working-galaxy-s5
There are countless processes that could be handled in a plugin such as this. If we could get a concrete list of high value processes, I think we could focus our direction on those. Feel free to comment here with requests!