Preparation Steps

• In a large skillet over medium-high heat, heat 3 tbsp. oil. Add finely chopped onion, cumin, 1 ½ tsp. salt, and 1 tsp. black pepper. Cook, stirring occasionally, until onion has softened, about 5 minutes. Add beans and 1 cup broth and cook, stirring occasionally, until most liquid has reduced, 5 to 7 minutes. Continue to cook, using a potato masher or fork to smash beans, until smooth, 3 to 5 minutes. Remove from heat and stir in lime juice.
• Meanwhile, in a medium pot over medium heat, heat remaining 2 tbsp. oil. Add sliced onion and remaining 1 ½ tsp. salt and 1 tsp. black pepper. Cover and cook, stirring occasionally, until onions have softened slightly, 3 to 5 minutes. Add garlic and jalapeño, if using, and cook, stirring, until fragrant, about 1 minute. Stir in green chiles and remaining 1 cup broth. Increase heat to medium-high and cook, stirring occasionally, until reduced by half, 5-7 minutes. Stir in chicken until warmed through. Remove from heat and stir in cilantro.
• Top tostadas with bean mixture, chicken mixture, romaine, avocado, and queso fresco. Garnish with more cilantro. Serve with lime wedges alongside.