In a medium bowl, combine all the ingredients for the marinade. Mix well. Add the steak cubes and marinate for 20 minutes at room temperature.
Put tomatoes cubes in a strainer or colander. Season with salt and toss gently to combine. Let them sit and drain for 30 minutes.
In a medium bowl, combine the tomatoes, onion, and cilantro. Season with salt and add half of the lime juice. Taste and adjust with more salt and lime juice if needed. Set aside.
Cut the avocado and remove the flesh with a spoon. Transfer the flesh to a medium bowl. Add onion. Mix with a spoon. Season with salt and add half of the lemon juice. Taste and adjust with more salt and lemon juice if needed. Set aside.
Preheat the oven to 350˚F (180˚C). Line a quarter baking sheet with a parchment paper or aluminum foil.
In a large skillet over high heat, warm 1 tablespoon vegetable oil. Remove the beef from marinade and add to the skillet. Cook until just no longer pink. Transfer to a medium bowl.
In a microwavable small bowl, place in ½ cup of refried beans. Heat in the microwave until warmed. Stir and mix.
To assemble, in the prepared baking sheet, smear ½ the refried beans at the bottom. Sprinkle with ¼ of cheese. Place ½ of tortilla chips. Sprinkle ½ of the beef over. Top with ¼ of cheese. Repeat the steps once again. Transfer the baking sheet to the oven. Bake for 8 – 10 minutes or until cheese has melted. Remove from oven.
Top with dollops of guacamole and sour cream. Sprinkle with pico del gallo. Serve immediately.