For 20 years, Harlem Rep. Charles Rangel has owned a beachfront villa in a sun-drenched Dominican Republic resort, yet has only sporadically declared income on the property in federal filings. While the villa was rented to paying guests for the past two years, for instance, Rangel reported no income from it in 2006 and 2007, The Post has learned. As a congressman, failure to fully list all income and investments can result in civil penalties or criminal charges. The powerful Ways and Means Committee chairman, a Democrat, owns "casita" No. 412 on the Caribbean Sea at the Punta Cana...