May I ask a favor? Could you please bring this racial curiosity to the attention of the school administration so you or they might recruit one or two non-Asians to participate in your program? You could teach this class for years with no black/white/Hispanic students participating, but why not set a personal goal of getting just one or two non-Asians to participate every year? You don't have to move mountains, just don't let the students decide their fate so early. Helping one interested student is enough (as a start :)
I used to teach a summer school in math in Koreatown (Los Angeles). All the students were Korean, and they all refused to participate on their school's math team because "they're all Chinese nerds with coke-bottle glasses." I'm black, so I was a little shocked because I never saw this in real-life before (Asians being intimidated by other Asians). Alas, I ignorantly grouped Asians together. Anyway, black, white, and Hispanic students experience the same intimidation. They need a little push to get over it.