In a sauté pan, over high heat, pour some oil and add the beef steak pieces. Sear and brown on all sides until well coloured. Transfer to the slow cooker bowl. Sprinkle the beef with the cayenne pepper, cumin, coriander seeds, smoked paprika, corn flour and toss to coat.
Then, add the onion, garlic, beef stock, tomato purée, green chilli, lime zest and juice. Cook on low for 8 to 9 hours or high for 4 to 5 hours. Once the beef is cooked prepare the sides. Cook the rice as per pack instruction in a saucepan and drain. Place the rice back in the saucepan while still hot and stir in the tin of black kidney beans. Drizzle some oil and keep aside until needed.
In the meantime, make the tomato salsa. In a small bowl, add the diced tomato with the diced red onion with the fresh coriander. Drizzle over olive oil, seasoning and stir. When ready to serve, shred the beef with two forks and stir to coat with the cooking juices. Serve the beef with some rice, extra fresh coriander, and a spoon full of tomato salsa.
Serve immediately with some sour cream depending on how spicy you like it.