Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Trim the woody ends from the asparagus spears and toss them on the baking sheet with 0.5 tablespoon of olive oil, 0.25 teaspoon of sea salt, and a pinch of black pepper.
Spread the asparagus in a single layer and roast for 12 to 15 minutes until the tips are slightly charred and the stalks are tender.
While the asparagus roasts, season the chicken breast on both sides with the remaining sea salt, black pepper, and dried oregano.
Heat the remaining 1 tablespoon of olive oil in a heavy-bottomed skillet over medium-high heat until shimmering.
Carefully place the chicken in the skillet and sear for 6 to 7 minutes per side, or until the exterior is golden brown and the internal temperature reaches 165°F.
Reduce the heat to low, add the minced garlic to the pan, and sauté for 30 seconds until it becomes fragrant without browning.
Drizzle the lemon juice over the chicken and sprinkle with red pepper flakes, swirling the pan to create a light, bright pan sauce.
Plate the seared chicken alongside the roasted asparagus, drizzling any remaining pan juices over the meat before serving.