Bring a large pot of water to a rolling boil and add a couple teaspoons of salt.
Add the elbow pasta to the boiling water, stir, return to a boil, then reduce heat slightly and cook until al dente (about 15 minutes for Fiber Gourmet Light elbows or according to package directions).
Drain the pasta in a colander and let it sit to remove excess water.
While the pasta cooks, drain the canned tuna in a fine-mesh strainer set over a bowl to remove oil; set tuna aside.
Chop 20 of the green olives and slice the remaining olives into rounds for garnish.
Finely chop the celery and slice the green onions.
Make the dressing by whisking together lemon juice (and zest if using) and green olive brine, then whisk in mayonnaise and, if desired, Szeged Fish Rub until smooth.
In a large bowl, combine the drained pasta, chopped green olives, chopped celery, and sliced green onions.
Add the desired amount of dressing and toss until ingredients are evenly coated; reserve any extra dressing for leftovers if you like.
Gently fold the drained tuna into the salad, keeping the tuna in small chunks and avoiding over-mixing.
Season to taste with salt and freshly ground black pepper, remembering the olives add saltiness.
Serve immediately or chill before serving.