Heat a nonstick skillet over high heat for one minute. Spray with pam and reduce to med-high. Place salmon on skillet and cook for 2 mins the flip and cook for 2 more minutes Let fillet cool for 5 minutes.
In bowl, use fork to flake salmon. Add carrot, celery, and onion and stir to combine.
In a medium bowl, whisk together yogurt, mustard, dill, lemon zest and paprika, salt and pepper. Pour yogurt mixture to salmon mixture until combined.
Toast bread and put half cup salmon mixture in sandwhich and top with cheese, lettuce and tomato.