1. Combine shrimp, 1/2 teaspoon salt, and pepper, tossing to coat shrimp. Heat a large nonstick skillet over medium-high heat. Coat pan with cooking spray. Add shrimp; sauté 4 minutes or until shrimp are done.
2. Combine rind and juice in a small saucepan over medium heat; add 2 teaspoons thyme. Bring to a boil; add butter, stirring constantly with a whisk until butter melts. Bring 6 quarts water to a boil; stir in 1 tablespoon salt. Add pasta; cook 10 minutes or until al dente. Drain, reserving 2 tablespoons pasta water. Add shrimp, butter mixture, reserved pasta water, and remaining 1/2 teaspoon salt to pasta, tossing to coat. Sprinkle with remaining 1 teaspoon thyme.