Not sure exactly what type of "design thinking" you are looking to learn. In my experience, a lot of people think about design only as it applies to visual/UX. Design Thinking, on the other hand, is more a way to problem solve and understand the issues at hand (and of course, how to solve them).

One resource I recommend is IDEO.org...it's tailored more towards humanitarian type Design Thinking, but it might be a good place to look depending, of course, on your needs ;)

https://www.ideo.org/approach