Prepare the Quinoa: Rinse 1 cup of quinoa under cold water. In a pot, combine the quinoa with 2 cups of water or broth and a pinch of salt. Bring to a boil; then reduce to a simmer, cover, and cook for about 15 minutes or until the water is absorbed. Fluff with a fork and set aside.
Grill the Salmon: While the quinoa is cooking, preheat your grill to medium-high heat. Season the salmon fillets with olive oil, salt, and pepper. Grill the salmon for about 6-7 minutes on each side or until cooked through and flaky.
Assemble the Bowl: In a large bowl, layer the cooked quinoa at the bottom. Add the baby spinach, diced cucumber, and sliced avocado on top. Place the grilled salmon fillets over the mixture.
Serve: Enjoy immediately! You can drizzle with a little extra olive oil or a squeeze of lemon for added flavor.