Heat the oil or lard in a large skillet over medium heat.
Add the chopped onion and red bell pepper (if using) and sauté until softened, about 5-7 minutes.
Stir in the minced garlic and cook for another minute until fragrant.
Add the cooked rice and black beans (along with a little of their liquid to help with moisture) to the skillet. Stir well to combine everything with the sautéed vegetables.
Add the chopped cilantro and Salsa Lizano (or Worcestershire sauce). Stir continuously, breaking up any clumps of rice or beans, and allowing the flavors to meld together. Cook for about 5-10 minutes, until the rice is heated through and slightly toasted, and the beans are well incorporated.
Season generously with salt and freshly ground black pepper to your taste. Stir one last time.
Serve hot, garnished with extra fresh cilantro.