Combine sour cream, mayo, water and lemon juice until smooth. Mix ingarlic powder, onion powder, salt and pepper and then set aside.
For the Wrap
On a cutting board, lay out the two tortillas. Place 2 slices of lettuce on each. Arrangetomato, avocado, red onion and cucumber slices onto one side of the tortilla.
Top each tortilla with half a can of tuna then drizzle the dressing over it.
Make the wrap by folding in the sides of the tortilla and then rolling it closed from oneend to another.
Enjoy as is or with additional garlic ranch dressing.