Mix celery, onions, carrots, olives. Add tuna and eggs, then add the noodles (still warm from cooking). Add the mayonnaise until everything looks moist. Then add salt and pepper to taste. Drizzle a little spicy mustard over the top and mix it in.
This fills a 2-quart dish. It's best to make a day ahead, but if you can't a few hours to chill is okay.