Ingredient Note: Plantains are a starchy, less-sweet relative of the banana. They are typically sold underripe, with yellow skin, but are best when the skin is almost completely black. Buy underripe plantains about one week in advance and ripen on the counter.
Heat 1 teaspoon oil in a Dutch oven over medium-high heat. Add pork and cook, stirring occasionally, until just browned, 2 to 3 minutes. Transfer to a plate using a slotted spoon.
Reduce heat to medium and add the remaining 2 teaspoons oil to the pot. Add onion, plantain (or sweet potato), bell pepper, cumin, pepper, salt and cinnamon and cook, stirring often, until the vegetables are beginning to soften, 3 to 5 minutes. Add orange juice, increase heat to high, and cook until most of the liquid has evaporated, about 1 minute.
Stir in water and black beans and bring to a boil. Reduce heat to a simmer and cook, stirring occasionally, until the onion and plantain are tender, 10 to 14 minutes. Stir in chiles, refried beans and the pork along with any accumulated juices. Increase heat to medium-high and cook, stirring constantly, until the mixture is thick and the pork is just cooked through, about 2 minutes.