Justin,
No, it's not possible. Twitter and VK (I think that's it) do not have any way to fetch the user's email address from those services. Because of that, JFBConnect can't automatically create the user, and is why they have to go through some sort of registration process.
If you want the smallest registration process, you can use the JFBConnect registration flow and basically disable all registration fields so all that's asked for is the user's email address. All other information can be imported automatically. Of course, you could show more information to request of the user since they already have to go through the flow.
Finally, if you haven't tried the setting, there's also the "Registration Component" setting in JFBConnect's configuration. With that, you can have the user go through the EasySocial registration flow, in case you like that better.
I hope that helps explain, but if you have any questions, just let me know.
Thanks,
Alex