Grate the cucumber on the large holes of a box grater. Place it in a clean kitchen towel or several layers of paper towel and squeeze firmly over the sink to remove as much liquid as possible.

Add the squeezed cucumber to a medium bowl with the Greek yogurt, olive oil, lemon juice, garlic, dill, salt, and black pepper. Stir until evenly combined.

Taste the dip and adjust with a small pinch of salt, more lemon juice, or dill if desired. For the best flavor, cover and chill briefly before serving if time allows.

Cut the pita breads into wedges. Warm them in a dry skillet over medium-low heat, in a toaster oven, or wrapped in foil in a warm oven until soft and pliable.

Serve the tzatziki with warm pita wedges. Add sliced vegetables, olives, or cooked chicken on the side if you would like a more filling lunch.