Preheat your grill or grill pan to medium-high heat and lightly grease the grates with a high-heat oil.
Pat the branzino fillets dry with a paper towel to ensure the skin becomes perfectly crispy.
In a small bowl, combine the minced garlic, finely chopped parsley, and chopped oregano.
Rub the fish fillets with half of the olive oil, then coat evenly with the herb-garlic mixture, sea salt, and black pepper.
Slice the lemon in half and toss the asparagus spears with the remaining olive oil and a pinch of salt.
Place the branzino skin-side down on the grill, along with the lemon halves (cut-side down) and the asparagus spears.
Grill the fish for 4-5 minutes per side until the flesh is opaque and flakes easily with a fork.
Remove the charred lemons and asparagus once they have developed grill marks and reached a tender-crisp texture.
Serve the grilled branzino immediately with a squeeze of the warm charred lemon juice over the top, accompanied by the asparagus and warm quinoa.