Sure, I've heard of this Processing language.... I've seen some of its code examples and used some of it too. I do a decent amount of data visualization in the courses I teach. I do not teach Processing myself, but I have several colleagues who do use it and teach it too.
Processing is breaking into the mainstream in several areas of application, it seems to me. There are several good books, so the documentation is relatively easy to find now.
What do you need to know?