1. Cook pasta according to package directions. Add peas to pasta during last 2 minutes of cooking. Drain and rinse with cold water; drain well.
2. While pasta cooks, combine mayonnaise and next 6 ingredients (through garlic) in a large bowl. Add pasta mixture and arugula; toss to coat.
3. Heat oil in a skillet over medium-high heat. Add prosciutto; sauté 2 minutes. Drain on paper towels. Sprinkle prosciutto over salad.