Preheat oven to 425°F (220°C).
Place trimmed asparagus on a baking sheet. Drizzle with 1 tablespoon olive oil, sprinkle with 1/2 teaspoon salt and 1/4 teaspoon black pepper. Toss to coat evenly and spread in a single layer.
Roast asparagus in the preheated oven for 12 to 15 minutes until tender and slightly browned.
While asparagus roasts, place peeled and cut potatoes and garlic cloves in a large pot. Cover with cold water and add 1/2 teaspoon salt.
Bring to a boil over high heat, then reduce heat to medium and simmer until potatoes are tender, about 15 minutes.
Drain potatoes and garlic well and return to the pot.
Add butter and warm milk to the potatoes and garlic. Mash with a potato masher or fork until smooth and creamy. Season with 1/2 teaspoon salt and 1/4 teaspoon black pepper. Keep warm.
Heat 1 tablespoon olive oil in a large non-stick skillet over medium-high heat.
Pat salmon fillets dry with paper towels. Season both sides with 1 teaspoon salt and 1/2 teaspoon black pepper.
Place salmon fillets skin-side down in the hot skillet. Cook without moving for 4 to 5 minutes until the skin is crispy.
Flip salmon and cook for an additional 3 to 4 minutes until salmon is opaque and flakes easily with a fork.
Remove salmon from heat and let rest for 2 minutes.
Serve each salmon fillet with a portion of roasted asparagus and garlic mashed potatoes.