In a 12-inch nonstick skillet over medium-high, heat the oil until shimmering. Add the pepper, onion and ½ teaspoon each salt and pepper. Cook, stirring occasionally, until the onion is light golden brown, about 5 minutes.
Stir in the tomatoes with juices, the harissa and ½ cup water. Bring to a simmer and cook, uncovered, stirring occasionally, until the pepper and onion are fully softened, 6 to 8 minutes. Taste and season with salt and pepper.
Reduce to medium-low, then use the back of a large spoon to make 6 evenly spaced indentations in the tomatoes and sauce, each about 2 inches in diameter. Crack 1 egg into each well, then sprinkle with salt and pepper. Cover and cook until the egg whites are set but the yolks are still runny, 5 to 8 minutes, rotating the skillet halfway through for even cooking. Remove from the heat, sprinkle with parsley and drizzle with additional oil.
