If you have ever wandered the narrow streets of San Sebastián (Donostia in Basque) or Bilbao and found yourself drawn into lively bars overflowing with colorful small bites on bread, some of them skewered on toothpicks, you have encountered one of Spain’s greatest gastronomic gifts to the world: the pintxo. Pronounced “PEEN-cho”. These vibrant, one-…