Tofu and Sweet Potato Curry

Name: Tofu and Sweet Potato Curry
Ingredients: 2 large or 3 medium sweet potatoes; 1 pound firm tofu, well drained and diced; One 14- to 16-ounce can low-sodium stewed tomatoes, chopped, with liquid; 1 to 2 teaspoons good-quality curry powder, or to taste; 4 ounces arugula or baby spinach, well rinsed; Salt to taste