Distributing content/assets separately

I wonder how does one distribute content/assets separately. So the application isn’t too bloated and content is downloaded when app starts. One of the reasons is the application max. size accepted by Play Store.
Is the APK extension file the way to go? And if so, how does one redirect ContentManager to proper directory?

I’ve been thinking about this a bit lately, I have some game ideas that would require moving to a “live-ops” model on content distribution. It shouldn’t be too hard, ContentManager takes a string which is the path to the content files, you can actually point that to anywhere on the filesystem. All you’d need to do is host the content somewhere, distribute a list of required content (something as simple as hosting a json file in a known location), download the files and point the ContentManager at the download location.