Greek Pork Tenderloin with Israeli Couscous

Name: Greek Pork Tenderloin with Israeli Couscous
Ingredients: 1 teaspoon ground allspice; 1 teaspoon dried oregano; 1/2 teaspoon garlic powder; 1 large pork tenderloin (about 1 1/4 pounds), trimmed; Kosher salt and freshly ground pepper; 3 tablespoons extra-virgin olive oil; 1 cup Israeli couscous; 1/4 cup crumbled feta cheese; 2 Persian cucumbers, halved and thinly sliced; 1/4 cup chopped fresh dill and/or parsley; 3 tablespoons chopped sun-dried tomatoes (not oil-packed); Juice of 1/2 lemon, plus wedges for serving