- Place a 10-inch (25 cm) wide, 2-inch (5 cm) deep cast iron pan directly on the barbecue grill. Preheat the grill, setting the burners to medium.
- Place the tomatoes and chili pepper in the hot, dry skillet. Close the barbecue lid and cook until the tomatoes burst and release their juices, about 8 minutes, stirring twice. Set aside in a bowl.
- In the same skillet, soften the onion, bell pepper and garlic in the oil for 4 minutes, stirring with a wooden spoon. Add the oregano and cumin. Cook for 1 minute while stirring. Add the vinegar, black beans and two-thirds of the tomato mixture. Season with salt and pepper.
- Using a spoon, make 4 wells in the mixture and break an egg into each one. Close the barbecue lid and cook for 6 minutes or until the egg whites are cooked but the yolks are still runny. Remove the skillet from the barbecue.
- Season the eggs with salt and pepper. Garnish with the remaining tomato mixture, the feta, cilantro and avocado, if desired. Serve with grilled soft corn tortillas, if desired.