Adjust oven rack to middle position.
Heat oven to 300 degrees.In a small bowl, mix sour cream, yogurt, cucumber, vinegar, 1 minced garlic clove, and salt and pepper to taste; set aside.
Place pitas in oven; bake until warm and pliable, 7 minutes. Cut in half. Meanwhile, heat oil in a large skillet over high heat. Carefully add onion; saute until spotty brown but still crisp, 2 to 3 minutes. Add turkey, oregano and remaining minced garlic; continue to sauteuntil heated through, another 2 minutes.
Serve, letting guests fill their own pitas with lettuce first, followed byturkey, tomatoes and cucumber sauce.
1/2 cup sour cream
1/2 cup plain low-fat yogurt
1/2 cup cucumber, peeled, gratedand squeezed as dry as possible
2 teaspoons red or rice wine vinegar
2 garlic cloves, minced
1/2 teaspoon Salt and pepper, to taste
4 large pitas
2 tablespoons olive oil
1 large onion, peeled, halved andcut into chunky wedges
3 cups leftover roast turkey, pulledinto bite-sized pieces
1 teaspoon oregano
1 1/2 cups shredded lettuce (preferably romaine)
1 cup cherry tomatoes, halved and lightly salted