After the eggs are hard-boiled and cooled, peel and slice them in half lengthwise, remove the yolks, and add them to a mixing bowl. Place 8 halves on one dish and the other 8 halves on another dish.
Mash yolks to a fine crumb with a fork. Add the mayonnaise, sour cream, Dion, red onion, salt, black pepper, and cornichons to the mixing bowl. Mix with a spoon until well combined. The mixture will be creamy.
Spoon about a teaspoon of the egg mixture into each egg half on their separate plates. If you have a very small cookie scoop, this makes the job easier.
On one of the plates with the 8 egg halves, sprinkle with smoked paprika. On the other plate with the other 8 halves, sprinkle the fresh chopped parsley.
On a serving platter, arrange the arugula to resemble a wreath. Gently and alternating between the two different egg platters, arrange the deviled eggs. Place two thin, small pieces of red pepper on one of the ends to resemble horns.