Preheat your grill to medium-high heat. In a bowl, toss the shrimp with olive oil, garlic powder, paprika, salt, and black pepper until well coated.
Thread the shrimp onto skewers for easy grilling. Grill the shrimp for about 2-3 minutes on each side, or until they are pink and opaque. Remove from the grill and set aside.
In a medium saucepan, bring the vegetable broth to a boil. Stir in the couscous, cover, and remove from heat. Let it sit for about 5 minutes, then fluff with a fork.
In a large bowl, combine the cooked couscous, cherry tomatoes, cucumber, red onion, and parsley.
Squeeze the lemon juice over the salad and toss to combine. Add the grilled shrimp on top and sprinkle with feta cheese if using.
Serve immediately or chill in the refrigerator for 30 minutes for a refreshing cold salad.