1. Peel shrimp; devein, if desired. Stir together shrimp and 1 Tbsp. olive oil in large nonstick skillet; sprinkle with pepper and salt.
2. Cook shrimp over medium-high heat 1 1/2 to 2 minutes on each side or just until shrimp turn pink. Remove shrimp to a large bowl, and toss with 1 tsp. lime juice. Cool completely (about 30 minutes). Finely chop shrimp.
3. Preheat oven to broil. Process parsley, sour cream, yogurt, and remaining 2 tsp. lime juice in a food processor or blender until parsley is finely chopped. Season parsley sauce with salt and pepper to taste.
4. Stir together shrimp, tarragon, and next 3 ingredients in large bowl. Place 1 Tbsp. shrimp mixture on top of each slice of French bread, and place on a baking sheet.
5. Broil 5 inches from heat 4 to 5 minutes or until shrimp mixture is lightly browned. Remove from oven, and drizzle with parsley sauce. Serve immediately.
*1 Tbsp. finely chopped fresh thyme may be substituted.