Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Press the extra 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, chickpeas, broccoli florets, and sliced red bell pepper.
Whisk together the olive oil and harissa paste, then pour over the vegetable mixture and toss until everything is evenly coated.
Spread the mixture in a single layer on the prepared baking sheet and roast for 25 to 30 minutes, tossing halfway through, until the tofu is golden and the broccoli is slightly charred.
While the bowl components roast, prepare the dressing by whisking together the tahini, lemon juice, minced garlic, and nutritional yeast in a small bowl, adding a tablespoon of warm water at a time until it reaches a smooth, pourable consistency.
Assemble the bowl by placing the roasted tofu and vegetables in a serving dish, drizzling generously with the tahini sauce, and finishing with a sprinkle of hemp hearts, sea salt, and black pepper.