To roast the eggplant, heat oven to 425 degrees. Smear a little oil on a rimmed baking sheet. Trim ends from the eggplant and cut into ½-inch-thick rounds (if any rounds are larger than 2 inches in diameter, cut them into half-moons). Scoop eggplant into a bowl and drizzle with oil and 6 tablespoons of the Salsa Negra. Toss to coat evenly. Spread on a prepared baking sheet and roast for 20 minutes or until the eggplant is soft and beginning to brown.
Puree the black beans in a blender or food processor, adding a little more bean liquid or water if necessary to get them moving through the blades. Scrape into a small (1- to 2-quart) saucepan and stir in enough liquid to give the puree the consistency of cream soup, usually a generous ¼ cup. Stir in the remaining 3 tablespoons of the Salsa Negra and simmer over medium-low heat for a few minutes to harmonize the flavors. Taste and season with a little more salt if the sauce needs it.
Spoon some warm sauce on each dinner plate to create a base for the other components. Top with a portion of the eggplant, dollop with crema and sprinkle with queso fresco and cilantro leaves. Your full flavored, meatless dish is ready to serve.