Preheat the oven to 375 degrees. Cook the empanadas according to the directions on the package (or follow the recipe in the menu if making them from scratch).
In a bowl mix the mayo, chipotle, lime, and cilantro in a bowl. Season with salt and pepper to taste.
Heat the oil in a saucepan over medium heat. Sauté the garlic, onion, and cumin until the onions start to soften. Add in the black beans and season with salt and pepper. Add 1/3 cup of water to the saucepan.
Low simmer for 15-20 minutes to concentrate the flavor. Remove from the heat and stir in the cilantro. Season with salt and pepper to taste. Using an immersion blender or stand up blender, pulse the black beans 2 to 4 times just to break them up a bit into a smooth dip. (if too thick after blending thin it out with a little broth)
Serve the empanadas with sauce. Top the black bean dip with cotija. Serve with tortilla chips. Garnish with cilantro.