We don't currently store this information in EasySocial. It's something we could investigate but similarly to us storing it in their database during registration, their app could look in our tables for this information for the user as well.
I'm not saying we can't push it to EasySocail, but there becomes a big risk of data consistency when you're trying to send the same information to multiple places when it's the same data. It's best to just store it in one place and multiple apps/components/plugins can access it as necessary.
In our case, it's as simple as:
JFBCFactory::usermap()->getUser($joomlaUserId, 'facebook');
That will have the user's token and other details we have for them which can be used to post.
I'm not sure what the EasySocial Facebook and Twitter Apps do offhand, but I hope that helps answer your question.
Thanks,
Alex