Open a pita and cut in half. Rub the surface with a clove of garlic, and drizzle with olive oil. Give a sprinkle of salt. Bake for 10 minutes, or until medium brown.
Put the parsley, mint leaves, celery leaves, and oregano in a bowl. In another bowl, add the tomato, cucumber, and onion. Add the 4 tablespoons oil, salt to taste, and lemon juice. Toss together to coat evenly.
Just before serving, add the herbs to the vegetable bowl with the chickpeas. Toss together, taste and adjust seasoning. Add the toasted pita bread that you crunch into your hands to make smaller pieces, and serve.