Rinse the quinoa under cold water and place in a small pot with 2/3 cup water or vegetable broth.
Bring quinoa to a boil, then reduce heat to low, cover, and simmer for 15 minutes until liquid is absorbed and quinoa is fluffy.
Season the top sirloin steak generously with sea salt and cracked black pepper on both sides.
Heat one teaspoon of olive oil in a cast-iron skillet over medium-high heat.
Sear the steak for 4-5 minutes per side for medium-rare, or until it reaches your desired level of doneness.
Remove the steak from the pan and let it rest on a cutting board for at least 5 minutes before slicing.
In the same skillet, add the remaining teaspoon of olive oil and the minced garlic, sautéing for 30 seconds until fragrant.
Add the green beans to the skillet with a splash of water, cover, and steam for 3-4 minutes until tender-crisp.
Remove the lid and sauté the beans for another minute to evaporate excess moisture.
Slice the rested steak against the grain.
Plate the fluffy quinoa, top with the sliced steak, and serve the garlic green beans on the side with a fresh squeeze of lemon juice over everything.