1. Preheat oven to 350°. Place potatoes in a small bowl, and drizzle with oil. Sprinkle with 1 tsp. kosher salt; toss to coat. Place on a baking sheet.
2. Bake at 350° for 40 to 45 minutes or until tender. Remove from oven, and let cool 15 minutes.
3. Cut each potato in half lengthwise. Carefully scoop out potato pulp into a bowl, leaving shells intact. Discard 4 potato shells. Place remaining shells on baking sheet, and bake 10 more minutes. Let cool 30 minutes or until completely cool.
4. Add mayonnaise, next 6 ingredients, and, if desired, celery seed, to potato pulp in bowl. Beat at medium speed with an electric mixer until blended. Spoon mixture generously into each potato shell. Cover and chill 2 hours. Sprinkle with paprika just before serving, if desired. Garnish, if desired.
Note: For testing purposes only, we used Wickles Original Pickle Relish.