Preheat your grill or grill pan to medium-high heat.
Pat the salmon fillet dry with a paper towel to ensure a clean sear.
In a small bowl, combine the garlic powder, dried oregano, sea salt, and black pepper.
Rub the spice mixture evenly over the flesh side of the salmon fillet.
Toss the asparagus spears with half of the olive oil and a pinch of salt.
Brush the grill grates with the remaining olive oil to prevent the fish from sticking.
Place the salmon on the grill skin-side down and cook for 4-5 minutes.
Carefully flip the salmon and grill for another 2-3 minutes until the fish is opaque and flakes easily.
Grill the asparagus alongside the salmon for 4-5 minutes, turning occasionally until charred and tender.
Remove from heat and finish with a fresh squeeze of lemon juice and a sprinkle of zest before serving.