After a search of more than a year, the Smithsonian has chosen Richard Koshalek to be the next director of the Hirshhorn Museum and Sculpture Garden. Koshalek presided over extraordinary growth in his 17 years (1983-99) at MOCA in Los Angeles; last year he was forced out as president of Pasadena’s Art Center College of Design in a conflict over tuition and a $50 million library designed by Frank Gehry.