Heat a large non-stick skillet over medium heat, add the oil then the onion and saute until golden, about 2 to 3 minutes. Add the tomatoes, harissa, salt and pepper and increase the heat to medium-high and simmer until the liquid reduces a bit, about 3 to 4 minutes. Reduce the heat to medium-low, carefully add the eggs, salt and pepper and cover. Cook until the top of the eggs set, about 4 to 5 minutes, or to your liking. Top with chopped fresh parsley or chives and serve.
