Translation:What are the Hungarian kindergarten teachers like?
When discussing groups and categories in Hungarian, the definite article is required. Consequently, without further context, it is impossible to distinguish whether this should be "Hungarian kindergarten teachers" as a general statement, or "the Hungarian kindergarten teachers" as a specific statement. Both should be accepted.
My understanding is that milyen refers more generally to the quality of a thing, not just its appearance. If someone asked me, "Milyen a feleséged?" (what is your wife like?), I could perhaps answer "Nagylelkű." (she is generous). But as English, when asked, "what does your wife look like?", a reply of "she is generous" doesn't make any sense.
Does that help?