Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Trim the Brussels sprouts and halve them; peel and slice the carrots into thin rounds.
Toss the Brussels sprouts and carrots on the baking sheet with the extra virgin olive oil, garlic powder, and half of the sea salt and black pepper.
Roast the vegetables for 20-25 minutes, tossing halfway through, until they are tender and caramelized.
While the vegetables roast, pat the tuna steak dry with a paper towel and season both sides with the remaining sea salt and black pepper.
Heat the toasted sesame oil in a cast-iron skillet over high heat until just smoking.
Sear the tuna steak for 1-2 minutes per side for a medium-rare center, then remove from the pan and let it rest for 3 minutes.
In a small bowl, combine the warm cooked quinoa and shelled edamame with the coconut aminos.
Slice the tuna steak into thin strips against the grain.
Plate the quinoa and edamame mixture, top with the sliced tuna and roasted vegetables, and garnish with sesame seeds.