Cajun Shrimp with Rémoulade Sauce

Name: Cajun Shrimp with Rémoulade Sauce
Ingredients: ½ c. light mayonnaise; 2 tbsp. ketchup; 2 tbsp. minced celery; 1 tbsp. grainy Dijon mustard; 1 tbsp. minced fresh parsley leaves; 2 tsp. fresh lemon juice; ½ tsp. Cajun seasoning (see Tips & Techniques); 1 green onion; 1 tbsp. Cajun seasoning (see Tips & Techniques); 1 tbsp. olive oil; 2 tsp. grated fresh lemon peel; 1¼ lb. large shrimp; Green-onion and lemon-peel slivers; Lemon wedges (optional)