If the phone is rooted... you should be able to use a root file explorer or terminal emulator... Most app data stuff is stored in /data/data/<APP PACKAGE>
And it looks like all the Jaxx stuff ends up in /data/data/com.kryptokit.jaxx
Unfortunately, I just did a quick check using Android on VirtualBox, and it looks like all the folders gets automatically deleted if you uninstall the app... if you don't have the wallet words, or a nandroid backup of your device from when you had Jaxx installed, chances are that your wallet (and coins) are gone
