Cook pasta according to package directions, adding fresh green beans to pasta the last 5 to 7 minutes of cooking. (Or, add frozen and thawed beans the last 3 to 4 minutes.) Rinse pasta and beans well under cold running water; drain thoroughly.
In a large mixing bowl combine Italian dressing, tarragon, and pepper. Add pasta, beans, and radicchio or cabbage; toss gently to coat. Serve on a bed of shredded spinach and top with the Gorgonzola cheese. Makes 8 side-dish servings.