In large pan, add walnuts to water, bring to boil and simmer until slightly tender, about 5 minutes. Add rice, cover and simmer until done, about 15 minutes.
In medium pan, cook chard in 2 cups water until tender, 2-3 minutes. Drain well.
In small bowl, stir flour into yogurt until smooth. Stir into rice, bring slowly to boil, stirring constantly, and cook, continuing to stir, until thickened, about 1 minute.
Add yogurt and cooked chard to rice. Stir in cilantro and mint. Season to taste with salt. Cook 3 minutes. Serve hot or cold.
Makes 4 servings. Each serving contains about 382 calories; 249 milligrams sodium; 3 milligrams cholesterol; 10 grams fat; 57 grams carbohydrates; 16 grams protein; 1.08 grams fiber.