There are three simple rules when planning a trip to Pike Pizza (which doesn’t actually serve pizza) on Columbia Pike in Arlington: Arrive hungry; Arrive early; Hog the salteñas. Usually available right when the restaurant opens and only in limited supply, salteñas are a version of empanadas, turnovers with your choice of meat combined with potatoes, peas, olives, and a hard-boiled egg. The chicken tends to complement the other ingredients better than the beef, but…