Preheat your grill or grill pan to medium-high heat and lightly grease the grates with a high-smoke point oil.
In a small bowl, whisk together the avocado oil, lemon juice, lemon zest, minced garlic, chopped dill, parsley, sea salt, and black pepper.
Trim the woody ends off the asparagus and place them on a tray next to the salmon fillet.
Brush the lemon-herb marinade generously over both the salmon and the asparagus spears until well coated.
Place the salmon on the grill skin-side down and cook for approximately 5 minutes without moving it to ensure a good sear.
Add the asparagus to the grill and cook for 4-5 minutes, turning occasionally until tender and lightly charred.
Carefully flip the salmon and cook for an additional 2-3 minutes until the internal temperature reaches 145°F and the fish flakes easily.
Remove the salmon and asparagus from the grill and serve immediately, garnishing with extra fresh herbs if desired.