Connect with your students on social media for sure that it will be much easier to know who really wants to be your audience. We are the same on the profession but I am not still practicing it as I am in-between if I want to continue it or not. By posting some crypto or blockchain-related content on your social media accounts and if ever there's a growing interest by some of your students on those posts maybe you can encourage them now if they want to dig deep on the technology or not. I advise you to start with just a few participants, stories may spread if it's good or not.

Just a suggestion I guess it will be good if it will not be within the school premises if you teach them why not teach them during weekends. And a fair advise it will be good if you really are that knowledgeable to the technology before teaching them.