Preheat your grill or a heavy grill pan over medium-high heat until hot.
Finely mince the garlic clove and chop the fresh parsley and dill.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, parsley, dill, sea salt, and black pepper.
Brush the herb marinade generously over the salmon fillet and the trimmed asparagus spears.
Place the salmon on the grill, skin-side down, and cook for approximately 4 to 5 minutes without moving it to ensure a golden crust.
Add the asparagus spears to the grill and flip the salmon fillet carefully.
Cook for an additional 3 to 4 minutes until the salmon is just opaque and flakes easily with a fork while the asparagus is charred and tender.
Remove from the heat and serve immediately while the flavors are fresh and vibrant.