Wrap beef in plastic, and chill in freezer until firm, about 1 hour. Using a very sharp knife, cut beef across the grain into 1/8-inch-thick slices. Gently pound slices between pieces of waxed paper. Refrigerate beef slices between pieces of waxed paper 1 hour (up to 2 hours).
Whisk together oil, 2 teaspoons lemon juice, 1/2 teaspoon salt, and a pinch of pepper in a medium bowl; set aside.
Cut pears into 1/2-inch-thick wedges. Toss with 2 tablespoons lemon juice in a bowl. Arrange beef in a single layer on serving plates. Drizzle with oil, and season with salt and pepper.
Toss arugula with the dressing, and arrange over beef. Arrange pears over arugula. Top with Parmesan; drizzle with oil, and season with salt and pepper. Serve with lemon wedges.