Start by patting the salmon fillets dry with paper towels, then brush both sides generously with olive oil and season with salt, pepper, and lemon zest. Set aside while you prepare the asparagus.
Trim the woody ends off the asparagus, keeping the spears whole. Toss them lightly with olive oil, salt, and pepper, ensuring each spear is coated evenly.
Preheat your grill to high heat until hot and slightly smoky. Carefully oil the grill grates to prevent sticking.
Place the salmon fillets skin-side down on the hot grill. You should hear a satisfying crack as the skin starts to crisp. Close the lid and cook for about 4-5 minutes.
Add the asparagus across the grill grates, turning occasionally, until they develop a slight char and become tender with a smoky aroma, about 7-8 minutes.
Flip the salmon carefully using tongs or a spatula, cooking for another 3-4 minutes until the skin is crispy and the fish feels firm but moist when pressed.
Remove the salmon and asparagus from the grill. Squeeze fresh lemon juice over the fish and spears, and sprinkle with chopped herbs if using, for bright flavor and freshness.
Let the salmon rest for a couple of minutes to allow the juices to settle. Plate the grilled fillets alongside the smoky asparagus spears, and enjoy the crispy, tender textures and vibrant flavors.
