Rinse shrimp; pat dry with paper towels. Finely shred 1 teaspoon peel from the lemon; set aside peel. Juice the lemon over a bowl; set aside juice. Cook pasta according to package directions.
Meanwhile, in 12-inch skillet heat olive oil over medium heat. Cook garlic in hot oil for 1 minute. Add shrimp; cook for 3 to 4 minutes, turning frequently until shrimp are opaque. Add spinach and drained pasta; toss just until spinach begins to wilt. Stir in Italian seasoning, lemon peel, and 2 tablespoons of the lemon juice. Season to taste with salt and pepper. Top with fresh dill. Serve at once.
Substitute bite-size pieces of deli-roasted chicken for the shrimp. For peppery bite, replace half the spinach with arugula.