Combine first 5 ingredients in a large zip-top plastic bag; add shrimp to bag. Seal bag, and marinate shrimp in refrigerator 15 minutes. Heat oil in a large nonstick skillet over medium-high heat. Add shrimp mixture, and sauté 3 minutes. Add mushrooms and carrot; stir-fry 2 minutes. Stir in pasta, vinegar, and salt, and cook for 2 minutes or until thoroughly heated. Sprinkle with onions. Garnish with shiitake mushroom and radish, if desired.