In a bowl, stir together the tuna, celery, tomatoes and mayonnaise.
Lay your tortillas out on a work surface. On each tortilla, lay down a lettuce leaf, then make stripes of the tuna mixture, grated carrot and avocado slices.
Lift one side of the wrap over the filling. Now fold over the top and bottom, enclosing the filling. Roll the whole thing toward the open side until it’s closed. Wrap it snugly in plastic wrap or parchment paper.
Recipe excerpted from The School Year Survival Cookbook.