Warm oil in a large dutch oven, then add the coriander and cumin seeds to fry for about 30 seconds on medium heat.
Add the onions, garlic, ginger, and bell pepper to sauté.
When the onions soften add the soaked black beans, sweet potato, and water.
Bring to a boil, then reduce to a simmer and cook the beans with the lid ajar for about 35 minutes. Add more water if necessary.
Once the beans are cooked and tender, add the coconut milk, lime, and bouillon. Stir well, then cook for another 15 minutes, or until the stew has thickened and the beans are tender.
Season to taste with more salt and cayenne pepper.
Serve over coconut rice (recipe below), and garnish with fresh cilantro and jalapeño pepper (or lemon).