I love finding unique ways of teaching skills! I never would've thought of using three trays to support organization and critical thinking skills but this book describes many wonderful activities using three trays. It's worth a try!
You may be thinking, why do I need to worry about this for my kindergarteners? They're little! Ok, maybe others will be thinking that. This article provides really nice background information to explain why it's worth your time and effort to teach analytical thinking skills to your little ones.