In the bowl of a food processor pulse together the basil leaves, 1 tablespoon of the garlic, the walnuts, and the Parmesan. With the food processor running, slowly drizzle in 1/3 cup of oil and season with salt and pepper, to taste.
In a medium saucepan over medium-high heat, bring 2 cups water and 1/2 teaspoon salt to a boil. Remove from the heat, stir in the couscous, cover, and let it stand for 5 minutes, or while you cook the shrimp. (Reserve 1 cup of the couscous for Round 2 Recipe Couscous Stuffed Tomatoes.) When you are ready to serve, stir half the basil pesto into the couscous. (Reserve the remaining basil pesto for Round 2 Recipe Shrimp Bruschetta.)
Heat the remaining 1 tablespoon of canola oil in large skillet over medium heat. Add the remaining 1 tablespoon of garlic and red pepper flakes and cook for 30 seconds. Add the broth and lemon juice and cook until it bubbles. Add the shrimp, season with salt and pepper, to taste, give it a good stir. Cook until the shrimp turn pink and are cooked through, about 4 minutes. Remove the pan from the heat and stir in the parsley. (Reserve 10 shrimp for Round 2 Recipe Shrimp Bruschetta.) Transfer the couscous to a serving platter. Spoon the shrimp and sauce over the couscous and serve immediately.