I don't think there is.
If your goal is to teach students how to interact with a SE site (which is great!), I think the only way to do that is having them actually interact with it. There's no simulator at the moment.
That's of course fraught with uncertainties - if the content they contribute is bad, it's likely to be a bad experience for them as they may get downvoted, closevotes, see unfriendly comments, etc.
New user accounts also have severe limitations in functionality (they can't upvote until they have 15 rep, they can't comment on other people's questions until 50, etc.) that make the mission difficult.
The best way to introduce students to the system might be having them ask a good question (perhaps cross-checked by you before submission). But it may be difficult for a group of students to come up with something that is good, and hasn't been asked to death yet.
If it were my choice, I'd give them an assignment with four options:
Ask a question. They should check out the "what can I ask here" guidelines. Offer them to send the question to you first to make sure it's OK. Tell them to stick around to provide clarification, etc.
Answer an existing question and earn at least one upvote on the answer. They need to make sure they check out the guidelines on what makes a good answer.
or, if they can't come up with either a question or an answer, they should earn 10 reputation points by making five good suggested edits that get accepted. (They should make sure they check out the guidelines of what constitutes a good edit.) Stress that mini-edits correcting a minor thing, while sometimes approved, aren't welcome; an edit is supposed to address all the issues a post has.
those who don't find themselves able to do either of these could research the site's guidelines, look at some Meta discussions, and write a couple of paragraphs about how the place works.