Tuna Melt Baguette

Tuna mix [tuna (chunk light tuna, water, vegetable broth, salt), mayonnaise {soybean oil, water, whole eggs, distilled vinegar, egg yolks, salt, sugar, lemon juice concentrate, calcium disodium edta (used to protect quality), natural flavors}, onion, celery, lemon juice {water, lemon juice concentrate and less than 2% of: lemon oil, sodium benzoate and sodium meta-bisulfite (preservatives)}, salt, black pepper], Baguette [unbleached enriched wheat flour (wheat flour, malted barley flour, niacin, iron, thiamine mononitrate, riboflavin, folic acid), water, salt, yeast], Tomatoes, Sliced cheese swiss (pasteurized part-skim milk, cheese culture, salt, enzymes)