Preheat the oven to 400°F (200°C).

Prepare two 12-inch square sheets of heavy-duty aluminum foil.

In a medium mixing bowl, toss the trimmed asparagus with 1 tablespoon of olive oil and a pinch of salt and pepper.

Divide the asparagus evenly between the two foil sheets, arranging them in a flat layer in the center.

Place one salmon fillet atop each bed of asparagus.

In a small bowl, whisk together the remaining olive oil, minced garlic, oregano, salt, and pepper.

Spoon the garlic-herb mixture over the top of each salmon fillet, spreading it evenly.

Arrange two lemon slices on top of each seasoned salmon fillet.

Fold the foil over the salmon and asparagus, crimping the edges tightly to create a sealed packet while leaving space for steam expansion.

Transfer the foil packets to a baking sheet and bake for 12 to 15 minutes, depending on the thickness of the fish.

Remove from the oven and carefully open the packets to avoid steam burns.

Garnish with fresh parsley and serve immediately within the foil or transferred to a plate.