In a medium bowl, whisk together the orange juice, lime juice, tomato paste, water, olive oil, cumin, oregano, minced garlic, paprika, and chopped cilantro. Pour this over the beef and onions in the slow cooker.
Place the lid on the slow cooker and cook on low for 8 hours.
Using two forks, shred the beef.
Warm the back beans and cook the rice.
Peel the plantain like a banana and slice into coins. Fry in a large non-stick skillet with coconut oil, for a few minutes per side, or until golden brown. Place on a paper plate when cooked, until all are ready. Do not drain on a paper towel, they will stick!
Serve shredded beef with black beans and white rice. Top with fried plantains and pineapple or mango salsa.