Mix together flour and salt in a large bowl. Drizzle oil into flour, mixing with a fork, then sprinkle in up to 1/2 cup water, 1 tbsp. at a time, mixing until dough just holds together. Knead dough until smooth and elastic, then shape into a ball, cover with a damp cloth, and refrigerate for 2 hours.
Put chard in a colander, sprinkle with 1 1/2 tbsp. salt, toss to mix, and set aside to drain for 20 minutes.
Serves 8.
Variation: To make a torta di funghi, or mushroom torta, trim and thinly slice 2 lbs. fresh porcini mushrooms or 2 1/2 lbs. portobello caps. Heat 1/4 cup extra-virgin olive oil in a large pan over low heat. Add 4 minced peeled cloves garlic and sauté until slightly golden, about 5 minutes. Add mushrooms and cook, stirring occasionally, until soft, about 30 minutes. Transfer mushrooms to a colander and allow to drain for 10 minutes. Mix together mushrooms and 1/2 cup minced fresh parsley in a bowl and proceed with combining step.