Rinse the quinoa under cold water and combine with 0.5 cup water in a small saucepan; bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes.
Preheat your oven to 400°F and line a baking sheet with parchment paper.
Trim the woody ends off the asparagus and toss the spears with the olive oil, half of the sea salt, and half of the black pepper on the baking sheet.
Roast the asparagus for 12-15 minutes until tender and slightly charred at the tips.
Pat the steak dry with a paper towel and season both sides with the remaining salt and pepper.
Heat a cast-iron skillet over medium-high heat with the avocado oil until the oil is shimmering.
Place the steak in the hot skillet and sear for 4-5 minutes per side for medium-rare, adding the minced garlic to the pan during the final minute of cooking.
Remove the steak from the pan and let it rest on a cutting board for 5 minutes before slicing against the grain.
Fluff the quinoa with a fork and serve alongside the roasted asparagus and sliced steak.