Cook rice according to package directions, using 2 cups water. Omit salt, fat, and seasoning packet; cool completely.
Section tangelos over a bowl; reserve 2 tablespoons juice.
Combine cooked rice, tangelo sections, apple, and next 4 ingredients in a large bowl; toss gently.
Whisk together 2 tablespoons tangelo juice, vinegar, and next 4 ingredients; drizzle over rice mixture. Sprinkle with pine nuts; toss well. Cover and chill up to 4 hours. Garnish with rosemary sprigs, if desired.