Pat the salmon fillets dry with a paper towel. In a small bowl, combine ½ teaspoon of the Kosher salt, ½ teaspoon of the black pepper, garlic powder, and onion powder. Season both sides of the salmon filets with the spice mixture.
Heat 1 tablespoon of the olive oil over medium heat in a large pan. Add the salmon fillets and sear for 3-4 minutes on each side, they should be mostly cooked through but not completely cooked. Remove the salmon from the pan and set it aside.
Reduce heat to medium and pour in the remaining ½ tablespoon of olive oil. Add in the onion and garlic. Cook until the onion has softened, about 2 minutes. Mix in the couscous and toast for 1 minute.
Add in the chicken broth and red pepper flakes. Bring the broth to a boil. Reduce the heat to medium-low so that it is simmering. Cover the pan with a lid and cook for 8-10 minutes until most of the liquid is absorbed.
Mix in the spinach lemon juice, lemon zest, dill, basil and parmesan. Pour in the remaining ⅓ cup of chicken broth. Season with the remaining salt and pepper.
Nestle the salmon filets into the couscous. Cover and simmer for 3-4 minutes until the salmon is fully cooked through. Remove the pan from heat, serve, and enjoy!