In a large oven-proof (preferably cast iron) skillet, heat 1 tablespoon olive oil. Saute the chard over high heat until wilted and the stems have begun to soften, about 5 minutes. Transfer the chard to a bowl, along with any juices.

Add another tablespoon of oil to the skillet. Saute the onion and peppers over medium-high heat until soft, about 8 minutes. Stir in the garlic, cumin, and harissa, if using. Cook until fragrant, 2 minutes. Carefully pour in the tomatoes. Bring to a simmer over high heat. Cook until the tomatoes have begun releasing their liquid, 5 minutes. Using a fork or masher, crush the tomatoes to break up the larger chunks and create a saucy consistency. Reduce the heat to medium-low and simmer, stirring occasionally, until the sauce has thickened and the tomatoes have lost their acidity, about 20 - 30 minutes.

Stir in the chard and simmer 5 minutes more. Create 4 large wells in the sauce. One at a time, crack the eggs into the wells. Simmer until the egg whites are set but the yolks are still runny, about 10 minutes. Garnish with the cilantro leaves and serve straight from the skillet alongside Sumac Roasted Potatoes.