For the Tzatziki Sauce, mix all ingredients in a medium bowl. Cover and refrigerate until ready to serve.
Preheat oven to 400°F. Drizzle 2 tablespoons of the olive oil on large foil-lined shallow baking pan. Set aside.
Place chickpeas, egg, spices and seasonings, salt and remaining 2 tablespoons oil in food processor; cover. Process until almost smooth, scraping down sides as necessary. Transfer to large bowl. Add flour, parsley and baking powder; mix well. Form mixture into 12 patties, each about 1/2-inch thick. Place on prepared pan.
Bake 20 minutes until golden brown, turning half way through cooking. Serve with Tzatziki Sauce in pita bread pockets, if desired.