Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper.
Press the extra firm tofu for at least 15 minutes to remove excess water, then slice it into 1-inch uniform cubes.
In a large mixing bowl, combine the tofu cubes and cherry tomatoes with the olive oil, garlic powder, onion powder, sea salt, and black pepper.
Spread the tofu and tomatoes in a single layer on the prepared baking sheet, ensuring they are not overcrowded.
Bake for 25 to 30 minutes, tossing halfway through, until the tofu is golden and the tomatoes have blistered and burst.
While the tofu bakes, place the cooked quinoa in a large serving bowl and set aside.
Remove the baking sheet from the oven and immediately add the baby spinach to the hot tray, tossing lightly until the leaves are just wilted.
Transfer the tofu, tomatoes, and spinach into the bowl with the quinoa.
Sprinkle the nutritional yeast, hemp seeds, and lemon juice over the mixture.
Gently fold all ingredients together until the quinoa is evenly coated and the flavors are well combined, then serve immediately.