Sicilian Orzo Salad

Name: Sicilian Orzo Salad
Ingredients: Kosher salt; 12 ounces orzo; 2 stalks celery, thinly sliced, plus 1/2 cup roughly chopped leaves; 3 tablespoons pine nuts; 1/3 cup extra-virgin olive oil, plus more for drizzling; 3 cloves garlic, thinly sliced; 1/4 cup roughly chopped pitted black olives, such as kalamata; 1/4 teaspoon red pepper flakes; 1 cup roughly chopped fresh parsley or mint (or a combination); 1 3.75-ounce can oil-packed sardines or one 5-ounce can oil-packed tuna (preferably Italian), drained and flaked; Freshly ground pepper; 1/2 cup grated ricotta salata cheese (2 ounces)