Season the beef with salt and pepper. Heat a Dutch oven over medium heat with 2 teaspoons vegetable oil; sear the beef in two batches, adding up to 2 teaspoons more vegetable oil, until browned on all sides, 4 to 6 minutes per batch. Using a slotted spoon or tongs, transfer the beef to a plate as it browns.
Reduce the heat to medium. Add the remaining 2 teaspoons oil to the pot; add the onion, red pepper and garlic. Cook, stirring, until onion is soft, 8 to 10 minutes. Stir in the cocoa, chili powder, oregano, cumin and coriander; cook until fragrant, about 1 minute. Add the corn meal and tomato paste and cook until the tomato paste sticks to bottom and caramelizes, about 2 minutes. Stir in 6 cups water, scraping tomato paste from bottom of pan; bring to a simmer. Add the reserved beef and beans; partially cover the pot and adjust the heat to maintain a gentle simmer until the beef is tender, 1 1/2 to 2 hours.
Serve chili with fresh salsa, lime wedges, and brown rice, if desired.