6 medium sweet potatoes
1/2 cup olive or vegetable oil
1/4 cup orange juice
1 tablespoon sugar
1 tablespoon cider or white wine vinegar
1 tablespoon Dijon mustard
1 tablespoon finely chopped onion
1 1/2 teaspoons poppy seeds
1 teaspoon grated orange peel
1/2 teaspoon grated lemon peel
2 medium tart apples, chopped
2 green onions, thinly sliced