The brute accused of punching a 9-year-old girl at Grand Central Terminal allegedly told police he launched the unprovoked attack because he was “thirsty,” prosecutors said Monday. The bizarre motive for Jean Carlos Zarzuela’s alleged Saturday assault was revealed by prosecutors during his arraignment during which he was ordered held on $100,000 bail — after being cut loose earlier this month following a similar attack. “I hit the girl in the face because I was thirsty,” Zarzuela, 30, allegedly told a detective, Manhattan Assistant District Attorney Shara Safer said during the arraignment. “Maybe I hit her in the face by...