Thread the strips of duck onto the skewers making folds, but not too tight, then place them on a large serving plate. Drizzle with Worcestershire sauce and add a generous amount of pepper.
Preheat the grill to medium-high heat. Once the grill is hot, clean it with a brush or barbecue scraper.
Add the duck skewers and grill for a total of 4 to 5 minutes, turning them once.
Remove from the grill and immediately serve 1 to 2 skewers per person over a bed of couscous and top with a generous amount of the pistachio and green onion sweet and sour salsa.
Place all the ingredients in a medium bowl and add salt to taste. Whisk together, cover and set aside until serving time.