Is there a way to view all of your featured answers or know which of your answers have been featured?
Technically no. Yes.
At the moment, you can't see all your featured answers in one place, but that will probably change at some point in the future.
You can, however, keep track of them "manually", so to speak.
As you know, Socratic sends a confirmation email for every answer that gets featured. You can use this feature + the collections feature to make a list of all your featured answers.
For starters, check out your Email settings and set the Featured Answers Emails button to "On".
Now, every time one of your answers gets featured, you will receive a confirmation email that contains the link to the answer.
At that point, you can simply save the confirmation emails in your inbox or use a collection to get all your featured answers in one place.
More on how the collections work
You can create a collection called My featured answers [or whatever] and include all your featured answers.
Just in case you haven't seen them, here are two of your latest featured answers
These were featured about 4 days ago.
So, to sum this up, you cannot see all your featured answers at the moment, but you can keep track of them yourself if you want.