1 teaspoon peanut oil 2 medium scallions, white and green parts minced separately and set aside 1 teaspoon minced peeled fresh ginger 1 garlic clove, minced 6 ounces lean ground beef 1 tablespoon creamy peanut butter or tahini 1 tablespoon lime juice 2 teaspoons fish sauce1⁄4 to 1⁄2 teaspoon chili paste 1 medium radish, minced 1 tablespoon chopped cilantro leaves 1 tablespoon chopped mint leaves