Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Press the firm tofu for at least 15 minutes to remove excess water, then slice it into 1-inch uniform cubes.
In a medium bowl, toss the tofu cubes with nutritional yeast, garlic powder, onion powder, sea salt, and black pepper until well-coated.
Spread the seasoned tofu on one half of the baking sheet and place the broccoli, bell pepper, and onion on the other half.
Drizzle the olive oil over the vegetables, tossing gently to coat, then bake for 25 to 30 minutes until the tofu is crispy.
While the pan is in the oven, finely dice the cucumber and whisk it together with balsamic vinegar, Dijon mustard, and dried oregano.
Remove the tray from the oven and transfer the roasted components to a large bowl, drizzling the cucumber balsamic dressing over the top.