Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Dice the red potatoes into half-inch cubes and toss them in a bowl with 0.5 tsp of olive oil, 0.25 tsp of sea salt, and half of the black pepper.
Spread the potatoes in a single layer on the baking sheet and roast for 15 minutes.
While potatoes roast, rinse the quinoa and place it in a small saucepan with 0.5 cup of water; bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until the water is absorbed.
In a small bowl, whisk together the remaining olive oil, lemon juice, dried oregano, dried thyme, and the remaining salt and pepper.
Brush the herb mixture generously over the salmon fillet.
Push the potatoes to one side of the baking sheet and place the salmon fillet on the other side, then roast for an additional 10 to 12 minutes until the salmon flakes easily with a fork.
Place the baby spinach in a skillet with a splash of water over medium heat and sauté for 1 to 2 minutes until just wilted.
Fluff the cooked quinoa with a fork and plate it as a base, topping with the wilted spinach, roasted potatoes, and the herb-crusted salmon.