Saute in oil, garlic, onion, bell pepper, ginger, serranos, cilantro and oregano. Saute until most of the oil has been absorbed about 5 minutes. Stir in vinegar and pineapple juice. Bring to a sizzle, then stir in pureed carrots and tomato puree. Blend and allow to cook to a thick paste. Add stock until the paste breaks down into a rich thick sauce. Lower the heat and add the beans. Fold gently to blend. Let beans simmer for 12 minutes. Add salt and pepper to taste and serve.