Bake the walnuts in an 8- or 9-inch baking pan in a 350° regular or convection oven, shaking pan occasionally, until nuts are golden beneath skins, 7 to 10 minutes.
Meanwhile, in a bowl, combine orange juice, vinegar, and olive oil. Add apples, persimmons, and toasted walnuts and mix to coat. Add salt and pepper to taste.
Nutritional analysis per 1/4 cup.