Richard Strauss’s Salome (1905) helped set the tone for iconoclastic opera in the 20th century. Shattering most of the genre’s conventions — formulaic plots, vocal characterization, propriety — this tale of lust, incest, and decollation may still shock some viewers, but it has become a modern classic. Although Washington National Opera last staged it as recently as 2002, Washington audiences should be pleased to have another chance to hear it, in an excellent concert version…