Bring 6 quarts water and 2 teaspoons salt to a boil in a large stockpot. Stir in pasta; partially cover, and return to a boil, stirring frequently. Cook 8 minutes or until pasta is almost al dente, stirring occasionally. Drain pasta in a colander over a bowl, reserving 2 cups cooking water.
While pasta cooks, heat oil in a Dutch oven over medium-high heat. Add garlic and prosciutto; cook 1 minute, stirring constantly. Add pepper; cook 2 1/2 minutes or until prosciutto is crisp, stirring frequently. Add reserved 2 cups cooking water and chickpeas; bring to a boil. Add broccoli rabe (do not stir); cover, reduce heat, and simmer 7 minutes or until broccoli rabe is tender. Uncover; simmer 15 minutes or until liquid almost evaporates. Add pasta, and cook 1 minute or until pasta is al dente, tossing to combine. Remove from heat; stir in cheese. Serve immediately.