Cook pasta according to package directions, omitting salt and fat. Drain; rinse with cold water, and drain again. Place pasta in a large bowl; set aside.
Peel and devein shrimp. Heat oil in a large nonstick skillet over medium-high heat until hot. Add shrimp and garlic; saute 3 minutes or until shrimp turn pink. Add dressing to skillet, deglazing skillet by scraping particles that cling to bottom. Stir in green pepper, ground pepper, and mushrooms. Bring to a boil; reduce heat, and simmer, uncovered, 2 minutes.
Add shrimp mixture to pasta; toss lightly. Serve warm or chilled. Garnish with lime wedges, if desired.