Preheat the oven to 425°F (220°C). Line a large baking sheet with parchment paper.
Cut the pressed tofu into 1-inch cubes. Toss with 1 tablespoon olive oil and the cornstarch until coated, then season lightly with salt.
Toss the cauliflower florets with the remaining olive oil, salt, and pepper.
Spread the tofu and cauliflower in a single layer on the baking sheet, keeping them separate.
Roast 25 to 30 minutes, flipping once, until the tofu is golden and the cauliflower is browned.
Whisk together the soy sauce, rice vinegar, maple syrup, garlic, ginger, chili flakes, and water.
Heat a skillet over medium heat. Add the roasted tofu and cauliflower, then pour the sauce over top.
Toss gently 2 to 3 minutes until the sauce thickens and coats everything. Top with scallions and serve.