Let's first make it clear that I really liked the movie. It even made me tear up, which is quite something for this old no-nonsense heart of mine (I think a friend once called me completely devoid of romanticism... I wanted to kick that friend, but it probably would've confirmed something to her). ANYWAY, now I'm going to sound like a spoil-sport and say that I don't really think the point of it was to make everyone think "what IS Asian?" but just as a way of showing the possibilities of such a nebulous concept as the Asian-American.
RTP (lazytalk for Renee Tajima-Pena) began trying to figure out what being Asian-American meant and how it fit into the US. By the end, it seems the answers to those are (respectively) "gee, that's a tough one" and "it may blow your mind, but they are all over the place and do not plan on leaving." And then RTP got married and moved on, which I think begets a pretty important point: The big, philosophical question wasn't the most important thing, in the end. The stories of all these different Asian-American people (RTP's included) are what make up Asian-America (or a tiny portion of it, at least).
So I walked away from the film with the idea that more people need to know more about Asian-Americans... and boy, ain't that the truth.
Oh, and just for kicks, here's a definition of an Asian American care of Google: