A couple of quick-thinking mensches saved a Brooklyn synagogue from burning down Sunday morning after an arsonist set fire to the wooden lectern. Yitzchok Friedman, 30, was changing the tire on his minivan at 10 a.m. when he spotted smoke billowing out of the Krasna Bais Medrash, located at 1462 38th St. in Borough Park. "I right away opened the door. I covered my face with my jacket," he told the Daily News hours afterward. After a quick look, he stepped back to dial 911 and grabbed a fire extinguisher from a paper goods store across the street. Moshe Friedlander,...