In a small bowl, mix together 1/2 cup lemon juice, olive oil, lemon peel, mustard, garlic, basil and pepper. Add the shrimp and mix to completely coat. Let the shrimp marinate for 30 minutes.
Once the shrimp have finished marinating, thread the shrimp onto metal or wooden skewers. Grill the shrimp over medium heat, rotating once, for a total of 3 to 4 minutes or until the shrimp has turned pink and is cooked through.
Prepare the couscous according to the box directions. After the couscous has finished cooking, add 1/4 cup lemon juice and 1/4 cup of Parmesan cheese and stir to mix. Keep covered.
Serve the shrimp over couscous and garnish with fresh chopped basil.