Step 1

Prepare a large bowl of ice water and set it to the side.

Step 2

Remove the leaves from the celery stalks. On a sharp angle, slice the celery as thinly as possible. Transfer the leaves and stalks to the ice bath.

Step 3

Slice the red onion as thinly as possible. Add the slices into the ice bath with the celery.

Step 4

Finely chop the chives and the dill and add them a large bowl. Zest in the lemon, then squeeze in the lemon juice. Add the mayonnaise, mustard, vinegar, a large pinch of salt, sugar, and mix. Taste and season with salt to taste.

Step 5

Finely chop the olives and add them to the dressing.

Step 6

Drain the celery and red onion (they should only soak a few minutes), and dry them in a salad spinner. Add them in to the bowl with the dressing and give everything a mix.

Step 7

Add the tuna into the salad. Add about half the oil/butter the tuna was stored in as well. Mix and season with more salt as needed. Finish with freshly ground black pepper.

Step 8

Position a rack in the center of the oven and set the broiler to high. Add an ounce of sliced cheddar to the top of each slice of bread. Broil for 2-3 minutes or until the cheese is melty. Serve alongside the tuna salad, for a tuna-melt vibe.