Near the Obama Center, Han Cha savors the art of high tea

“Do you want milk for your matcha?” asked Heiji Choy Black, the partner and operator at Han Cha, the Asian fusion high tearoom that she helped open inside Stony Island Arts Bank in South Shore earlier this year. Choy Black recently debuted the tearoom, and companion bar Yunomi, with the artist Theaster Gates to enable folks to interact with Gates' ceramics and hopefully boost traffic to his South Side art center. Gates saved the distressed Arts Bank building from demolition in 2013 when he…