Start by pressing the tofu. Wrap the block of tofu in a clean kitchen towel and place it on a plate. Set a heavy object on top, like a cast-iron skillet, and let it sit for at least 20 minutes.
In a mixing bowl, whisk together the tamari, rice vinegar, maple syrup, garlic powder, and onion powder.
Once the tofu is pressed, cut it into bite-sized cubes or slabs.
Place the tofu pieces in the bowl with the marinade. Gently toss to ensure each piece is well-coated. Cover and let it marinate for at least 15 minutes.
Preheat your oven to 400°F (200°C).
Line a baking sheet with parchment paper. Spread the marinated tofu in a single layer on the sheet. Bake for 25-30 minutes, flipping halfway through.
Once baked, remove the tofu from the oven and let it cool for a few minutes. Garnish with sesame seeds, sliced green onions, chives, and red pepper flakes if desired. Serve warm.