Bring a pot of salted water to a boil. Using a sharp knife, make a small X on the bottom of each whole tomato. Place the tomatoes in the boiling water and cook for 1 minute. Remove and place in a bowl of ice water. Cool the tomatoes completely. Remove from the water and peel the skin off each tomato. Quarter each tomato 3/4 of the way to the bottom. Remove the seeds. Place the tomatoes in a large glass pan. Season the tomatoes with salt and pepper. In a small mixing bowl whisk together the oil, mustard and honey. Season with salt and pepper. Pour the marinade over each tomato. Cover with plastic wrap and refrigerate for at least 6 hours. Remove from the refrigerator and pour off the marinade into a medium size bowl. In a saucepan, add the crab boil and lemons. Bring the mixture to a boil. Add the shrimp. Cover and remove from the heat. Allow the shrimp to sit in the water for 8 minutes or until the shrimp turn pink and tails curl completely. Remove from the water and cool completely. Add the shrimp, corn, diced tomatoes, onions, olives, chervil and garlic to the bowl of marinade. Mix well. Season with salt and pepper. Place the tomato in the center of each serving plate. Spoon the shrimp salad in the center of each tomato. Garnish with sprigs of fresh chervil.