Preparation

• Heat the oven to 425ºF. Grease a 1-1/2 qt. baking dish with oil and line a baking sheet with foil. Set the tomatoes in a colander over the sink and sprinkle with 1 tsp. of the salt.
• Heat the oil in a large (12-inch) skillet over medium-high heat until shimmering hot. Reduce the heat to medium, add the onion, sprinkle with 1 tsp. salt, and cook, stirring, until softened and translucent, 4 to 6 minutes. Add the garlic and chili powder and cook, stirring, for 1 minute. Add half of the black beans, the chipotles and adobo sauce, and 3/4 cup water and bring to a boil. Cook until the liquid reduces by about half, 2 to 3 minutes.
• Transfer the bean mixture to a food processor, add the vinegar, and process until smooth. Let cool for a couple of minutes and then transfer to a large bowl. Add the rest of the beans, the tomatoes, corn, half of each of the cheeses, and 1/2 cup of the cilantro. Mix well and season to taste with salt and pepper.
• Transfer to the baking dish and sprinkle with the remaining cheese. Bake on the foil-lined baking sheet (to catch drips) until the cheese melts and browns around the edges, about 15 minutes (longer if refrigerated). Sprinkle with the remaining cilantro and serve with the tortilla chips for dipping.