Falafel with Spicy Yogurt Sauce

Name: Falafel with Spicy Yogurt Sauce
Ingredients: 1 container (6 oz) plain low-fat yogurt; 1 clove garlic , pressed or grated; 1 teaspoon fresh lemon juice; 1/4 teaspoon cayenne pepper; 1/8 teaspoon salt; For the Falafel:; 2 cans (15.5 oz each) chickpeas, drained and rinsed; 1 cup packed fresh parsley; 1/2 cup packed fresh cilantro; 2 cloves garlic , halved; 2 green onions , chopped; 1/4 cup all-purpose flour; 1 teaspoon ground cumin; 1 teaspoon ground coriander; 3/4 teaspoon salt; 1/4 teaspoon pepper; Vegetable oil; 2 pitas , halved; 1 to 2 tomatoes , sliced; 1/2 cucumber , sliced