Heat oven to 400°F.In a 10 to 12 inch, oven safe skillet, melt butter over medium heat. Add garlic and saute for about 1 minute, until fragrant.Add black beans, spinach, and salt. Cook until spinach is wilted, stirring occasionally.Pour salsa over the top of the bean mixture.Gently crack the eggs one at a time on top of the salsa. Top with queso fresco.Place skillet on a rack in the middle of the oven. Cook for about 10 to 15 minutes, until eggs are white but are still jiggly when the pan is moved.Meanwhile, warm tortillas over the flame of a gas stove or in a microwave covered in a paper towel.When the eggs are done, top with black pepper, coarse salt, fresh cilantro and more questo fresco.Serve immediately over warmed tortillas with avocado and lime wedges.