Prepare the lettuce: Wash and dry the lettuce leaves thoroughly using paper towels or a salad spinner.
Prep the vegetables: Slice the avocado, tomato, and cucumber, julienning the cucumber for easier wrapping.
Lay out lettuce leaves: Place the largest, most intact lettuce leaves on a clean work surface or large plate.
Add spread: Spread a thin layer of hummus or Greek yogurt ranch down the center of each lettuce leaf, adding a small amount of mustard if using.
Layer the turkey: Place 2-3 slices of turkey down the center of each lettuce leaf, overlapping slightly without piling too high.
Add vegetables: Top the turkey with 2-3 slices of avocado, tomato slices, cucumber, and a small amount of shredded carrots, keeping the filling centered.
Season: Sprinkle lightly with salt and pepper.
Wrap and serve: Fold the bottom of the lettuce leaf up over the filling, then fold in the sides and continue rolling like a burrito, or eat them open-faced with a fork and knife.
Secure if needed: If taking these to go, wrap each one in parchment paper or plastic wrap to hold them together during transport.