In a small bowl, whisk together mayonnaise, ketchup, pickle juice, mustard, Worcestershire sauce, salt, and pepper. Set aside or refrigerate until ready to serve.

In a large skillet over medium-high heat, cook the ground beef for 6–8 minutes until browned and cooked through. Drain excess grease and set aside.

Wipe out the skillet and spray with nonstick spray. Heat over medium heat. Place one tortilla in the skillet. On one half, layer 1/2 cup cheese, 1/4 of the cooked beef, and pickle slices if using. Sprinkle another 1/2 cup cheese on top and fold the tortilla in half.

Cook each quesadilla for 2 minutes per side until golden brown and cheese is fully melted. Transfer to a plate, cover to keep warm, and repeat with remaining ingredients. Cut each quesadilla in half.

Place one wedge of lettuce on each plate. Top with chopped shallots and tomatoes. Drizzle with some of the special sauce.

Plate two quesadilla halves per serving alongside the salad. Drizzle both with additional special sauce and serve extra sauce on the side.