non-traditional method

In my experience, they're not asking for you to know about every possible kind of non-traditional approach. I think the question speaks more to how open you are to trying different ways of teaching and how current you intend to keep yourself on teaching practices. "Non-traditional" may refer to something that might have been around for a very long time (such as a Montessori approach). I've even heard the term applied to the use of Bloom's taxonomy in the development of curriculum.

If you know a lot about alternative methods of teaching, ask them to specify their approach and then tell them how much you love that way (unless you absolutely hate it).

If you don't know a lot about that topic, or you don't want to take the chance, just say tell them about how much you think outside the box, etc. That's all they're looking for anyway.

I was asked a very similar question in an interview once, and I had to ask them to clarify what they meant because it was a term with which I wasn't familiar. (Ironically, it came from someone who had been one of my methods professors - I wanted to say, "You never taught me about that.") I then found something within their description to comment on, but I also took the opportunity to ask them how I could find out more about the topic because I appreciate that an interview can be a learning experience as well. I didn't get the job, but at least I got something out of it.