First, prepare the beans.
Rinse them thoroughly, then place them in a large saucepan and cover with water by about 2 inches.
Bring to a rolling boil, then reduce the heat and simmer, uncovered, for 10 minutes.
Remove the pan from the heat, cover it, and let the beans stand for 1 hour.
Finally, drain the beans in a colander and give them one last rinse.
Transfer the soaked and rinsed beans to a 3. 5 to 4-quart slow cooker.
Pour in the 5 cups (1200 ml) of fresh water and stir in the chopped onions, drained mushrooms, Creole seasoning, and minced garlic.
Cover the slow cooker and cook until the beans are tender. You can cook on the LOW setting for 11 to 13 hours or on the HIGH setting for 5. 5 to 6. 5 hours.
Once the beans are tender, if you were cooking on low, switch the slow cooker to the HIGH setting.
Stir in the uncooked instant brown rice, green pepper strips, and the entire can of undrained diced tomatoes.
Cover again and cook on HIGH for an additional 30 minutes, or until the rice is cooked through and the peppers are tender-crisp.
Serve warm, with a dash of your favorite hot pepper sauce if you like a little extra kick.