Peel cucumbers, remove seeds, cut the whole cucumber into quarters, and slice 1/2 thick pieces from each quarter.
Quarter the red onion and cut into thin slices.
Combine cucumbers, and red onions in a medium size bowl. Add vinegar, sugar, salt, and red pepper flakes. Mix to combine. Let marinate at room temperature for at least 1 hour.
Cut the tomatoes in half, and remove seeds by scooping them out with a large spoon. Cut seeded tomatoes into 1/2 thick slices.
Once ready to serve, add tomatoes, and fresh basil. Stir to combine.
To serve pitas, add cooked chickpeas, tzaziki sauce, marinated salad, and romaine lettuce to pita bread.
Serve with the marinated salad on the size as well. Enjoy!