1. Preheat oven to 450°.
2. Heat a small saucepan over medium heat. Coat pan with cooking spray. Add shallots and garlic to pan; cook for 2 minutes, stirring frequently. Place 1 cup crab in a food processor. Add the shallot mixture, 1/4 cup water, pepper sauce, and Cajun seasoning to crab; process until smooth. Spoon mixture into a large bowl, and stir in remaining crab, mayonnaise, and the next 5 ingredients (through black pepper).
3. Transfer the mixture to a 1-quart glass or ceramic casserole dish coated lightly with cooking spray. Combine panko and chives in a small bowl; sprinkle over crab mixture. Coat panko mixture with cooking spray. Bake at 450° for 30 minutes or until browned and bubbly. Let stand 5 minutes.