Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Press the firm tofu with a heavy object for 10 minutes to remove excess moisture, then cut into 1/2-inch cubes.
In a large mixing bowl, combine the tofu cubes, rinsed chickpeas, broccoli florets, and cauliflower florets.
Drizzle the olive oil over the mixture and season with sea salt, black pepper, garlic powder, and smoked paprika, tossing well to coat evenly.
Spread the vegetables and tofu in a single layer on the prepared baking sheet.
Roast for 25 to 30 minutes, tossing halfway through, until the vegetables are tender and the tofu is golden brown.
While the bowl base roasts, whisk together the Greek yogurt, lemon juice, and nutritional yeast in a small bowl until smooth.
Divide the roasted mixture into bowls, drizzle generously with the lemon-yogurt sauce, and garnish with hemp seeds before serving.