In a small saucepan, combine the dry quinoa with 0.5 cup of water, bring to a boil, then cover and simmer for 15 minutes until fluffy.
Toss the asparagus spears with 1 teaspoon of the olive oil and a pinch of salt, then roast at 400°F for 10 minutes until tender.
Pat the tuna steak completely dry with paper towels and season both sides with sea salt and black pepper.
Heat the remaining olive oil in a cast-iron skillet over high heat until shimmering.
Sear the tuna for 90 seconds per side for a perfect rare-to-medium-rare center, then remove from the pan to rest.
In a small bowl, whisk together the lemon juice, lemon zest, minced garlic, parsley, and oregano to create the herb sauce.
Slice the tuna against the grain and serve over the quinoa with asparagus, drizzling the zesty sauce over the top.