Pat dry the tuna steak with paper towels. Season both sides with salt and black pepper, using about 1/2 tsp of salt and 1/4 tsp of black pepper in total.

Heat 1/2 tbsp of olive oil in a non-stick skillet over medium-high heat. Once the oil is shimmering, add the tuna steak.

Sear the tuna for about 2-3 minutes on each side, until a golden crust forms. Don't overcook if you prefer it rare inside.

Remove the tuna from the skillet and let it rest on a cutting board for a few minutes. Meanwhile, prepare the asparagus.

Trim the woody ends from the asparagus. In the same skillet used for the tuna, add the remaining 1/2 tbsp of olive oil.

Add the asparagus to the skillet. Season with a pinch of salt and the remaining black pepper, and sauté for about 5 minutes, until they are tender-crisp.

While the asparagus is cooking, slice the lemon in half. Juice one half of the lemon and cut the other half into wedges for serving.

Reheat the cooked quinoa pilaf if it's not already warm. Plate the quinoa by placing it as a bed on each plate.

Place the seared tuna steak on top of the quinoa pilaf, and arrange the asparagus spears around it.

Drizzle the plate with fresh lemon juice and garnish with the lemon wedges. Serve immediately.