Trim fat from steak; place steak in a shallow dish. Pour wine over steak, and sprinkle with 1/4 teaspoon Cajun seasoning. Cover and marinate steak in refrigerator 1 hour.
Cook pasta according to package directions, omitting salt and fat. Drain; rinse with cold water, and drain. Place in a medium bowl. Stir in mushrooms and next 4 ingredients. Combine mayonnaise, vinegar, and remaining 1/2 teaspoon Cajun seasoning; spoon over pasta mixture, and toss gently. Cover and chill.
Remove steak from marinade, and discard marinade. Place steak on rack of a broiler pan coated with cooking spray. Broil 5 1/2 inches from heat (with electric oven door partially opened) 5 minutes on each side or to desired degree of doneness. Cut steak diagonally across grain into 1/4-inch slices; cut slices into 1-inch pieces. Add steak to pasta mixture, and toss gently.