I found it on an article :
If you call openWithDefaultApplication in a directory, it will open in your application by default for file explorer (Finder, Windows Explorer, Nautilus, etc.)
This did not work because my application was intended for Air 1.5, so I just added the following line to my application.xml and the problem was resolved:
<application xmlns="http://ns.adobe.com/air/application/2.0">