In 10-inch skillet over medium heat, melt remaining 2 tablespoons butter. Add onions; cook 2 to 3 minutes, stirring frequently or until onions are softened. Sprinkle with flour; cook and stir 3 minutes. Stir in reserved liquid from can of frijoles negros. Reduce heat to medium-low; cook until thickened, about 4 minutes. Stir in the frijoles negros, chicken, corn, roasted peppers, 1 tablespoon chopped cilantro, garlic salt, cumin and pepper sauce. Bring to a boil; reduce heat to medium-low. Simmer 10 to 15 minutes, stirring frequently or until most of the liquid is absorbed. Drain raisins; chop raisins and stir into chicken mixture. Cool slightly.