Sprinkle the eggplant with salt and let drain 10 minutes.
In a large skillet with a lid, heat the oil, three turns of the pan, over medium-high. Add the onion, olives, chile, garlic and spices. Cook, stirring often, until the onion softens, about 5 minutes. Add the eggplant; partially cover and cook, stirring occasionally, until softened, about 10 minutes. Stir in the tomato sauce and harissa. Using the back of a spoon, make 4 evenly spaced wells in the eggplant mixture. Crack the eggs, then pour one into each well. Reduce the heat to medium. Cook until the whites are set, about 5 minutes. Spoon the shakshuka into 4 shallow bowls; top with cilantro. Serve with the pita.