Carefully remove the yolks from the halved eggs and push them through a sieve into a mixing bowl. Add the mayonnaise, Creole mustard, Creole seasoning, and caper juice and mix until smooth and well-blended. Stir in the celery, chopped green onions and shrimp. Taste and adjust the seasoning if necessary.

Transfer the yolk mixture to a piping bag fitted with a large plain tip, and pipe the filling into the hollow of each egg half. Garnish with the sliced green onion tops and a sprinkling of cayenne pepper if desired. Serve immediately, or cover lightly with plastic wrap and chill for up to several hours or up to overnight before serving.