Cook Quinoa: Pour the chicken stock into a medium pot and bring it to a boil over medium-high heat. Add the quinoa, reduce the heat to low, cover, and simmer for about 15 minutes, or until the liquid is absorbed.
Prepare Kale: While the quinoa cooks, cut the kale leaves away from the thick stems. Chop the leaves into bite-size pieces.
Cook Kale: Bring the water to a boil in a large pot over high heat. Add the chopped kale and cook for about 2 minutes, just until tender and bright green, then drain well.
Mix Salad Base: Add the cooked quinoa and drained kale to a mixing bowl. Stir until evenly combined.
Prepare Salmon: Place the salmon fillets on a foil-lined rimmed baking sheet. Leave space between the pieces so they bake evenly.
Make Pesto Sauce: Add the lemon juice, pesto, and Dijon mustard to a small bowl. Whisk until smooth.
Season Salmon: Sprinkle the salmon fillets with the salt and black pepper. Season the tops evenly.
Coat Salmon: Spoon the pesto sauce over the salmon fillets. Spread it across the tops so each piece is covered.
Bake Salmon: Bake the salmon at 400°F for 10 to 12 minutes, or until it flakes easily with a fork and reaches 145°F in the center.
Finish and Serve: Serve each salmon fillet with the quinoa kale salad. Sprinkle the crumbled feta cheese over the salad before serving.