Brooklyn’s “First Lady” Jamie Markowitz really knows how to give critics of her husband, Borough President Marty Markowitz, a tongue lashing. We’re told Jamie “stuck her tongue out” at a neighborhood activist who opposed Markowitz’s plan to bring an amphitheater to Coney Island. A spy said Jamie pulled off the ineloquent insult when she spotted Ida Sanoff, who had led a fight to block the Beep’s project, while they dined at Gargiulo’s in Coney. Witnesses said Jamie — whose spouse tried to justify taking her on freebie trips by claiming the “first lady of Brooklyn” should be viewed in the same league as Michelle Obama — walked up to activist Sanoff and her husband, Jeff, flashed her tongue for a few awkward moments and then strutted away. Ida told The Post’s Rich Calder that Marty, seated two tables away, “avoided eye contact [with her] all night. I was in shock,” Ida said, adding, “What a lack of class.” Markowitz said through his rep that he didn’t see his wife stick out her tongue or commit any other lingual lapse. Jamie declined to comment.