1. Heat a large skillet over medium-high heat. Add 1 1/2 teaspoons oil to pan; swirl to coat. Sprinkle steak with 1/2 teaspoon salt and pepper. Add steak to pan; cook 4 minutes on each side or until desired degree of doneness. Place steak on a cutting board; let stand 5 minutes. Cut across the grain into thin slices.
2. Combine remaining 2 tablespoons oil, remaining 1/4 teaspoon salt, vinegar, and shallot in a mini food processor; pulse until mixture is almost smooth.
3. Arrange one-fourth of watercress on each of 4 plates. Top watercress evenly with onion and pear; sprinkle with cheese. Divide steak evenly among salads; drizzle 1 tablespoon vinaigrette over each serving.