At the Tenement Museum yesterday afternoon, a naturalization ceremony was held for 15 new American citizens. The U.S. Department of Citizenship & Immigration Services chose the Lower East Side setting. Judge Robert Katzmann administered the Oath of Allegiance to immigrants from 13 countries: China, the Czech Republic, the Dominican Republic, Germany, Ireland, Italy, Japan, The Netherlands, New Zealand, Nigeria, Philippines, Spain and Uruguay. Last year, about 84,000 people became new American citizens in New York.