In a 3- to 4-quart pan over high heat, bring rice, 1/2 teaspoon salt, and 2 cups water to a boil. Cover, reduce heat, and simmer until rice is tender to bite, about 20 minutes. Scrape rice into a wide shallow bowl, fluff with a fork, and let stand until cool, about 30 minutes.
Meanwhile, in an 8- to 10-inch frying pan over medium heat, frequently stir walnuts with 1 tablespoon oil until nuts are golden beneath skins, about 5 minutes.
Pour nut mixture over rice. Add remaining olive oil, and lemon juice, chives, and parsley; add salt to taste. Mix with a fork. Sprinkle salad with rosemary blossoms.