I am half white and half Asian. I usually identify as Asian, but would it hinder me to put Asian on my application as opposed to biracial since a lot of unis seem to be over representing the Asian population?
You could do either, but I assume that somewhere in your application you would want to make it known that you are Hmong given that Hmong students are underrepresented.
^ I agree. Somewhere on your application make it clear that you are Hmong, as it is an under represented group.