Preheat oven to 375 degrees.
Chop tomato, red onion, cilantro, oregano and red bell pepper. Slice avocado into small chunks.
Place black beans, tomato, cilantro, oregano, red onion, pepper and avocado in a bowl. Season with salt and pepper. Pour lemon juice on top, and toss to combine evenly.
Place mixture in a 6x9 or other small baking dish. Crumble the queso fresco cheese evenly on top. Bake in the oven until cheese is melted, around 10 minutes.
Serve warm with tortilla chips.