hi source
I �m not sure if I can help you or not but I always thought that critical thinking depends on how you deal with things. what I mean to say is that it depends on the questions you ask or the activities you give.
In our lesson plans we are usually asked to include different levels of questions which also should include questions that need (high order of thinking).
If this is what you mean and you need a topic to deal with this subject I suggest topics that allow students to give reasons for causes or effects of some phenomena and much better if they are asked to give solutions. some of my favorite topics that help in such things are (environment, scientific discoveries, generation gap).
Again I �m not sure if this would help but I wish you best of luck.
have a nice time