Press the tofu to remove excess moisture for 20–30 minutes using a tofu press or by wrapping the block in paper towels and setting a weight on top.
Preheat the oven to 375°F (190°C) and line a rimmed baking sheet with parchment paper or a silicone baking mat.
Cut the pressed tofu into roughly 3/4-inch cubes.
Make the marinade in a medium bowl by whisking together the tamari, rice vinegar, maple syrup, garlic powder, and onion powder until combined.
Add the tofu cubes to the marinade and gently toss with a spatula to coat. Let sit and marinate for 10–15 minutes, stirring occasionally so the sauce is absorbed evenly.
Arrange the tofu in a single, separated layer on the prepared baking sheet. Spoon any leftover marinade over the tofu if desired.
Bake for 25–30 minutes, turning or tossing the cubes halfway through, until the edges are golden brown.
Remove from the oven and garnish with sesame seeds, sliced green onion, chives, or red pepper flakes as desired, then serve warm.
