Boil a pot of water and add 1 tablespoon of salt. Once water is boiling, add couscous and cook until al dente (about 5 minutes). Set aside.
In a baking tray, add the bell peppers, zucchini, garlic, cherry tomatoes, feta cheese and shrimp. Sprinkle salt, pepper, cayenne, oregano and two tablespoons olive oil. Broil on high until shrimp is pink and feta is browned. Remove baking tray from oven and add couscous, scallions, red onions, capers, olives, dill, lemon juice and 1 tablespoon olive oil. Mix well.
Place salad in serving bowl and serve at room temperature.