Add 1 cup (250 ml) of water to a medium pot and bring to a boil over high heat.
Once boiling, quickly stir in the salt and couscous. Turn off the heat then cover and let sit for 5 minutes.
Fluff the cooked couscous with a fork and let it cool at room temperature for 30 minutes. Meanwhile, prep the other ingredients.
Add the lemon zest, dill, parsley, and feta to the cooled couscous and toss until well combined. Set aside while you make the shrimp.
Add the shrimp, 1 tbsp of olive oil, and the salt and pepper to a large bowl. Toss until well coated.
Heat a large pan over medium-high heat. Let it preheat for 1-2 minutes until it gets nice and hot.
Spread the shrimp out in the pan and cook for 2-3 minutes on each side or until the shrimp are pink, opaque, and lightly browned on both sides. Set aside on a plate.
Reduce the heat to medium and heat the remaining 1 tbsp of olive oil. Add the onions and sauté until translucent and lightly browned.
Toss in the garlic and stir for about 30 seconds until fragrant.
Add the harissa and tomato paste and stir for a few seconds to combine. Pour in the chicken broth and stir until you have a thick sauce. If it's too thick, add a little more chicken broth.
Turn off the heat and add back the shrimp, tossing until well coated. Add salt to taste.
Immediately serve the shrimp over the herbed couscous and garnish with fresh parsley.