Spoon beans into a 3- to 4-quart pan. Coarsely mash beans with a potato masher or the back of a spoon.
Step 2
Place over medium-low heat and stir occasionally until beans are hot, about 5 minutes.
Step 3
Meanwhile, heat a grill pan or 12-inch nonstick frying pan over high heat.
Step 4
Cut steak in half crosswise.
Step 5
Rub meat all over with olive oil and season to taste with salt and pepper.
Step 6
When pan is very hot, add steak. Cook, turning occasionally, until meat is seared and done to your liking, 2-4 minutes for rare depending on thickness of meat.
Step 7
Transfer meat to a cutting board and let stand 3 minutes. Cut meat across the grain into thin slices, then cut into bite-size pieces.
Step 8
Squeeze lime over meat; toss to coat in juice. Place tostada shells on 4 dinner plates. Top with equal portions of beans and meat.
Step 9
Sprinkle equally with cheese and romaine hearts, then drizzle with 1/2 cup salsa. Serve, offering additional salsa to add to taste.
We have updated our privacy commitment and are now collecting cookies to provide you with ads tailored to your interest across the internet. For more information about cookies and how to disable cookies, visit our privacy commitment.Learn More about Privacy