Drain the tuna thoroughly. Press the lids into the cans to squeeze out excess water or oil. Less moisture means a firmer, less soggy wrap.
Mix the dressing. In a medium bowl, whisk Greek yogurt, mayonnaise (if using), Dijon, lemon juice, a pinch of salt, and pepper. Taste and adjust acidity and salt.
Add the tuna and veggies. Flake the tuna into the bowl.
Fold in celery, onion, cucumber, and herbs. Add a small pinch of garlic powder if you like.
Adjust the texture. If the mixture feels too dry, stir in a teaspoon of olive oil or a splash more lemon. If too wet, add a bit more tuna or a spoon of yogurt to balance.
Warm the tortillas. Briefly heat them in a dry skillet or microwave for 10–15 seconds.
This makes them more flexible and less likely to tear.
Layer and assemble. Lay out a tortilla. Add a handful of greens, then 1/4 of the tuna mixture. Add extras like tomato slices or avocado if using.
Wrap it tight. Fold in the sides, then roll from the bottom up, keeping the filling snug.
Slice in half on a slight diagonal if serving right away.
Serve or pack. Eat immediately, or wrap each in parchment or foil for an easy grab-and-go meal.