Peel and cut the sweet potato into a small dice (see notes), remove outer skin from the scallion and slice it, and roughly chop the spinach (separate stems as far as possible).
If you prefer, you can toss the sweet potato cubes with oil on a baking sheet/tray and roast at approximately 400F/200C for around 20 - 25 minutes until tender and gently brown. You can also do this ahead (eg when roasting other things) and warm them through, if serving warm. Alternatively, you can pan-fry the sweet potato in a skillet/frying pan by warming around half the olive oil over medium heat, adding the cubes of sweet and cooking, turning now and then, until gently browned on around half the sides and the cubes are tender to a knifepoint.
Meanwhile, cook the quinoa according to packet instructions. You typically need twice as much water as quinoa by volume. Place both in a small pan, cover and bring to a boil, reduce to a simmer and scrape down any grains that get stuck on the side. Cook for approximately 10 minutes until the water is absorbed and the quinoa opens up little tendrils. Add a little more water if needed if the water appears to be absorbed but the quinoa is not yet cooked. Remove from heat.
Warm the rest of the olive oil in a small skillet, or use the same skillet as the sweet potato and add more oil, and add the scallions and spinach stalks. Cook for a couple minutes until they soften then add the spinach leaves and wilt down. Remove from the heat.
If serving the bowl warm, warm the steak through over medium heat briefly on both sides then slice (if serving cold or preparing ahead, you can simply slice).
Divide the cooked quinoa between two bowls, each topped with spinach, sliced steak, sweet potatoes and raisins.
Mix together the dressing (lemon, tahini, olive oil and honey) until smooth and pour over the top of both bowls.
This can be eaten warm or cold. It makes a great lunchbox (good mixed too) and you can make extra of everything and eat over a couple days, with variations as suits such as using leftover roast vegetables.