This is my recipe for Arroz con Habichuelas. It may not be traditionally Puerto Rican as they use sofrito (the pepper, onion, tomato and garlic all processed together) but it is pretty close.
1 1/2 cup dried kidney beans, washed, soaked overnight and cooked, save 1 cup of the liquid
2 cups white rice
1 green pepper, diced
1 large onion, diced
5 large garlic cloves, minced
1 large ripe tomato, diced
2 envelopes of Sazon, I prefer Goya
2 tsp. Adobo seasoning, again, I prefer Goya
3 cups chicken broth
2 tbsp olive oil
Salt and pepper to taste
Heat a Dutch oven and add the oil. Fry the garlic, peppers, onions until soft and then add the tomatoes. Cook a few minutes and then add the Sazon and adobo. Add the rice and cook for another 2 minutes or so. Add the beans and the liquid it cooked in as well as the chicken broth. Bring to a boil and then cover and lower heat to low. Cook until all the liquid is absorbed.