Toss the shredded lettuce into a bowl. Add the mayo and a splash of red wine vinegar, then mix until creamy.
Sprinkle in a generous amount of Everything But the Bagel seasoning and season with salt and pepper to taste.
Dice the tomato and stir it into the lettuce-mayo mixture.
Cook the bacon until crispy (microwave or stovetop).
Place the bread on a baking sheet, top with Swiss cheese, and broil until melted and bubbly.
Assemble: layer the bacon on the bread, top with a generous scoop of the lettuce-tomato mix, and serve.