Cut cucumber in half lengthwise and grate into a medium mixing bowl. Add yogurt, sour cream, lemon juice, and 1 tablespoon Greek seasoning. Stir to combine.
Season with salt and pepper.
Refrigerate for at least 1 hour. Serve with toasted pitas chips.
Preheat oven to 350 degrees F. Spray baking sheet with olive oil cooking spray; set aside.
Cut each. pita bread into 8 triangles. Place on baking sheet, in a single layer. Lightly spray with cooking spray and sprinkle with remaining 2 teaspoons Greek seasoning. Bake for 10 minutes. Remove from oven; let cool.