Scenic San Juan peninsula looks a little like Miami Beach, with new hotels and condos cutting a pretty figure against the deep blue ocean and sky. At the heart of the new waterfront development is the $188-million, 580,000-square-foot Puerto Rico Convention Center, the largest in the Caribbean, which opened 18 months ago. Here, one of the warehouse-like exhibition halls housed Circa Puerto Rico ’07, Mar. 30-Apr. 2, 2007, the second annual installment of Puerto Rico’s new international art fair.