Spinach-Artichoke Pizza

Preheat oven to 400 degrees F. Cut bread in half lengthwise, then cut each piece in half across. With hands, press bread to flatten. Line large cookie sheet with foil. Arrange bread, cut sides up, on prepared pan. Brush with oil and sprinkle with 1 cup mozzarella. Bake 5 to 7 minutes or until cheese melts. In large bowl, stir together spinach, cream cheese, yogurt, Parmesan, garlic, and 1/4 teaspoon each salt and pepper until combined. Divide mixture among pieces of bread, spreading evenly. Top with artichokes and remaining 1/4 cup mozzarella. Bake 12 to 18 minutes or until golden brown. Grate peel of half of lemon over pizzas. Garnish with chives.