In a large bowl, whisk together two 7-ounce containers greek-style yogurt, 2 tablespoons extra-virgin olive oil and 1 tablespoon chopped fresh dill. Using the flat side of a knife, smash 2 chopped cloves garlic with 1/2 teaspoon salt. Whisk the paste and some pepper into the yogurt mixture. Squeeze dry one 10-ounce package thawed frozen chopped spinach; stir into the yogurt mixture. Sprinkle with dried chopped mint and 2 tablespoons chopped toasted walnuts. In a small bowl, whisk together 1 tablespoon each extra-virgin olive oil and pomegranate juice; drizzle over the dip before serving. Serve with crackers, pitas or crudites.