Heat the oil over medium heat in a large skillet. Add the onions and a pinch of salt and cook, stirring, until soft and translucent, 5 to 7 minutes. Add the garlic, cumin, harissa, smoked paprika, red pepper flakes, another good pinch of salt and a few turns of black pepper. Cook until it's all dreamy-smelly, another 2 minutes. Stir in the tomato paste, followed by the chopped tomatoes and sugar, and simmer until slightly thickened, 10 minutes more. Taste the sauce and adjust the seasonings.
Make 8 little wells in the sauce and crack in the eggs. Simmer until the egg whites are set but the yolks are still runny, about 10 minutes. (You can either baste the eggs with sauce during cooking or just let them be in a sunny-side-up situation.) Off the heat, drizzle with olive oil and sprinkle the eggs with a little salt and pepper. Scatter the feta and parsley over all.