To make pickled celery: Use microwave or kettle to bring water to boil. Pour into large mason jar; add white vinegar, sugar, salt and peppercorns. Stir well to dissolve salt and sugar.
Add celery and dill. Cover with lid and chill 1 hour to overnight.
To make egg salad: Add eggs to medium saucepan and fill with cold water until eggs are covered. Over medium-high heat on stovetop, bring to boil. Turn off heat and cover with lid. Let sit 10 minutes. Drain and add eggs to bowl full of ice-cold water. Chill at least 10 minutes before peeling.
Chop hardboiled eggs and add to mixing bowl. Add mayonnaise, pickled celery, green onion, mustard, hot sauce, tarragon and celery salt then stir to combine. Serve in sandwich or wrap, or with crackers.