For what its worth, here is my two cents worth.
Teaching legal terms / concepts in English is a very specific topic and my guess is that you will have clients/students who already have a grasp of the language but want to learn more about specific legal terms / concepts. Because of that, your course can probably be tailored to the specific group you are working with & once you identify their needs, the course content will follow. Therefore, if you want to take any courses that can help, you can try taking some training courses specifically geared towards training adults or working with internationally trained professionals.
Mount Royal University has some interesting courses in their coned calendar, plus you can check out Advance Consulting for Education for some ideas as well.