In a small food processor or blender combine lime juice, cumin, cayenne, garlic, jalapeno, and 1 tablespoon vegetable oil and puree until smooth. In a shallow dish combine the beef with half of the vinaigrette tossing it to coat well, and let it marinade for 15 minutes. Reserve remainder of the vinaigrette.
In a large skillet, heat 1 tablespoon of the oil over moderately high heat until it is hot but not smoking, in it stir-fry the beef for 2 minutes, or just until it is still pink, and transfer the beef to a bowl.
In a large bowl combine the lettuce, corn, red onion, red bell pepper and cilantro. Whisk the reserved vinaigrette, if necessary, and pour over the salad, tossing to coat. Taste and adjust seasoning with salt and pepper. Divide the salad between two plates and top with the cooked beef in a decorative pattern. Garnish with lime wedges and cilantro sprigs.
Recipe courtesy of Gourmet Magazine