Preheat your grill or grill pan to medium-high heat.
Mince the garlic clove and finely chop the fresh dill and parsley.
In a small glass bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, dill, and parsley to create the marinade.
Season the salmon fillet and the trimmed asparagus spears with sea salt and black pepper.
Brush half of the prepared lemon-herb marinade over the salmon and asparagus, ensuring they are evenly coated.
Place the salmon on the grill, skin-side down, and cook for 4-5 minutes without moving it to achieve a good sear.
Add the asparagus to the grill alongside the salmon and cook for 3-4 minutes, turning occasionally until tender and slightly charred.
Carefully flip the salmon and grill for another 2-3 minutes until the internal temperature reaches 145 degrees Fahrenheit.
Remove the salmon and asparagus from the heat and drizzle with the remaining marinade before serving immediately.