In a large skillet, cook beef over medium heat. Drain well and return to pan. Mix in beans, chili powder, salt, and pepper; cook for 1 minute. Stir in 1/4 cup salsa and heat through.
Mix together remaining salsa and lime juice; set aside. Divide lettuce among serving bowls. Add meat mixture, avocado, tomato, red onion, and salsa mixture. Finish by topping each salad with a handful of tortilla strips.