The dish's spicy radish salad perfectly complements the grilled meat at the core of the recipe.
In a medium bowl, mix the radishes with the jalapeño, red onion, olive oil and lime juice and season with salt and pepper.
Set the tostada shells on plates and spoon the sour cream on top. Cover with the iceberg lettuce and sliced steak. Spoon the radish salad over the steak and sprinkle with the cilantro leaves. Serve with lime wedges.
Variation Make mini versions of this tostada using tortilla chips, or skip the tostada and roll the steak and salad in soft corn or flour tortillas.