In the basin of a 3 ½- to 4 ½-quart slow cooker, combine the rinsed black beans, undrained diced tomatoes, frozen stir-fry vegetables, frozen okra, and Cajun seasoning.
Stir everything together until well combined.
Secure the lid and cook on the LOW setting for 6 to 8 hours or on the HIGH setting for 3 to 4 hours, until the vegetables are tender and the flavors have melded.
Serve the hot Cajun bean mixture generously over fluffy cooked rice.
Garnish with a sprinkle of fresh chopped green onions, if desired.
While designed for convenience, you can substitute the frozen stir-fry mix with 1 large freshly chopped bell pepper and 1 chopped yellow onion.
