Prep the mix-ins: Finely chop the celery, onion, and herbs. Thin slices keep the wrap tidy and easier to bite.
Make the dressing: In a medium bowl, stir together cottage cheese, Greek yogurt or mayo, Dijon, lemon juice, and garlic powder.
Season lightly with salt and pepper.
Add the tuna: Flake the drained tuna into the bowl. Fold gently until the mixture is combined but not paste-like. Adjust seasoning, lemon, and mustard to taste.
Warm the wraps: Briefly warm tortillas in a dry skillet or microwave for 10–15 seconds.
A warm wrap is more flexible and less likely to tear.
Layer the greens: Place lettuce or spinach down the center of each wrap. This creates a barrier so the filling doesn’t make the tortilla soggy.
Add the filling: Spoon the tuna cottage cheese mixture over the greens. Top with tomato and avocado if using.
Roll it up: Fold the sides inward, then roll tightly from the bottom up.
Slice in half if you like.
Serve or pack: Eat right away, or wrap snugly in parchment or foil for lunch later.