Braised Harissa Eggplants & Greens

Name: Braised Harissa Eggplants & Greens
Cuisine: Moroccan, African
Ingredients: 3 tablespoons extra-virgin olive oil, divided; 1 (about 1 pound) eggplant, cut into ½-inch cubes; Kosher salt; Freshly ground black pepper; 1 small yellow onion, finely chopped; 3 garlic cloves, minced; 1 tablespoon harissa, plus more as needed; 1 teaspoon ground cumin; 2 pounds plum tomatoes, or Roma tomatoes, chopped; 1 can chickpeas, drained and rinsed; 1 bunch (about 8 ounces) lacinato kale, stemmed, leaves torn into bite-size pieces; 1 teaspoon fresh lemon juice