Melt 2 teaspoons butter in medium saucepan over medium heat. Add onion and cook 5 minutes or until tender. Add garlic and cook 30 seconds.
Stir in black beans with their liquid and Skinny Girl Chipotle Ranch Dressing and bring to a boil. Reduce heat and simmer 10 minutes or until most of the liquid is absorbed. Remove beans from the heat and mash with fork or immersion blender. et aside.
In large nonstick skillet, cook chorizo until lightly browned and hot. Set aside.
In same skillet, melt remaining butter and cook eggs 3 to 4 minutes, or until the whites are set and the edges are fully cooked.
Place a tostada on each plate. Top each tostada with the beans and an egg. Being careful not to break the yolk, gently top each egg with chorizo and Pico de Gallo. Drizzle with additional dressing.