Steam the sweet potatoes until done but still crisp (or you can roast them in 400F degree oven with a little olive oil for 12-15 minutes).
Heat the oil in a saucepan.
Add the couscous to the pan, and stir to coat with oil. Add the boiling water and bay leaf. Cover. Reduce heat to low and simmer for 10-15 minutes until the water is absorbed.
Uncover and fluff gently with a wooden spoon.
Cover and set aside.
While couscous is cooking, put the zest, orange juice, vinegar, cherries and cranberries in a small saucepan and bring to a boil over medium-high heat.
Remove orange and vinegar mixture from heat and set aside until the fruit is plumped up, about 3 minutes.
Drain, reserving liquid.
Scrape the couscous into a large bowl; add the sweet potatoes and fruit.
Add pistachios, scallions, parsley, salt and pepper.
Add 2 tablespoons of the orange and vinegar mixture and 1 tablespoon of olive oil. Stir to combine. If the finished product is not moist enough, add a little more of the orange/vinegar mixture.
Serve warm or at room temperature or chilled. It is excellent any way you eat it!