Q:

How to launch a chrome packaged app using a URL scheme

I have a chrome packaged app that I update form time to time - when I'm creating an update I want to send email to subscribed customers with a link the that extension -that will launch it.
Anyone knows if there is a chrome url scheme i can use?

A:

Currently this is not possible, but there is an API proposal and an implementation being developed for a chrome-app://appid URL schema that would do pretty much what you describe. 
Follow the status here

