Vienna’s monthly summer block parties, “Chillin’ on Church,” will begin tomorrow, June 21st with a performance by the Deja Gruv Band. The parties are sponsored by Ben and Jerry’s, who will have a food truck on location along with the following vendors: Blue City Foods– Indian street food Chix N’ Stix– Wings, chicken tenders, fries, hot dogs  DC Tapas Truck– Spanish style tapas …