Preheat your grill or grill pan to medium-high heat.
In a small glass bowl, whisk together the avocado oil, lemon juice, lemon zest, minced garlic, finely chopped parsley, dill, sea salt, and black pepper.
Pat the salmon fillet dry with a paper towel to ensure a clean sear and prevent sticking.
Brush the herb marinade generously over both the salmon fillet and the trimmed asparagus spears.
Place the salmon on the grill, skin-side down, and cook for approximately 5 minutes without moving it to develop a crust.
Add the asparagus to the grill and flip the salmon carefully, cooking both for an additional 3-5 minutes until the salmon is opaque and the asparagus is tender.
Remove from the heat and let the salmon rest for 2 minutes to lock in the juices before serving.