zippy tuna melts

Ingredients

• 6 tablespoons mayonnaise
• 2 cans 6oz each solid white tuna, drained
• 1/4 cup finely chopped celery
• 2 - scallions, finely chopped
• 2 tablespoons chopped parsley (i used dried)
• 2 teaspoons apple cider vinegar
• 1 tablespoon whole grain mustard
• 1 tablespoon prepared horseradish
• 4 slices rye bread, lightly toasted
• 4 slices lacey swiss cheese (or your choice of cheese)
• 2 - tomatoes, sliced (i used grape tomatoes, what i had)
• - salt and pepper to taste