Make dressing first. Whisk lemon juice, Dijon mustard, agave, and olive oil together in a small bowl. Add shallot and dill. Season with salt and pepper to taste. Set aside.
Make the quinoa pilaf. In a small pot, add the oil and shallot. Cook for 2 minutes until softened. Add quinoa and saute for 2 more minutes. Add broth and bring to a simmer. Cover, reduce to low, and cook for 14-15 minutes or until craters form in the quinoa and most of the liquid is absorbed. Turn off the heat. Place a clean thin kitchen towel on top and replace lid. This will keep it warm and fluffy until your other ingredients are cooked.
Meanwhile, while quinoa is cooking, pat salmon dry with paper towels and season lightly with salt and pepper on both sides. Heat oil in a nonstick skillet over medium-high heat until just smoking. Lay fillets in skillet and cook until browned on first side, about 3-5 minutes, depending on size and thickness of your fillets. Gently flip fillets. Reduce heat to medium and continue to cook until fish is flaky, but still pink and translucent in the center when checked with a tip of a paring knife (for medium-rare), 2 to 4 minutes. Transfer to a plate and tent loosely with aluminum foil to keep warm until ready to serve.
To the oil left in the pan, add the garlic slices and cook over medium heat until fragrant and golden brown. Remove garlic slices to a paper towel-lined plate. Add half of the asparagus to the skillet with tips pointed in one direction and the remaining spears with tips pointed in the opposite direction. Sprinkle with salt and cover. Cook until spears are browned on one side, but still crisp, about 2-3 minutes depending on thickness of asparagus. Uncover and cook while stirring for 1 minute more, or until crisp tender. To plate, add a mound of quinoa pilaf to each plate. Place the salmon fillets on top. Top with the herb dressing, and place asparagus pieces on the side. Top asparagus with the reserved toasted garlic slices.