Prepare all ingredients as listed above by slicing, peeling, and measuring.
Lightly toast the slices of sourdough bread.
Assemble the Sandwich: Spread mayonnaise on one side of each slice of bread. On one slice, layer arugula, spinach, tomato, turkey, provolone cheese, cucumber, onion, and pepperoncini. Place sliced avocado on top of the veggies. Season with salt pepper and oregano.
Top with the second slice of bread, mayo-side down. Press gently to secure the sandwich, then slice in half.
Prepare the Lemonade: Mix lemon juice, water, and sugar to taste. Serve over ice if desired.
Serve the sandwich with carrot, hummus, pickle, and lemonade