To make the marinade, stir the soy sauce, rice vinegar, maple syrup, sesame oil, and ground ginger together in a small bowl or dish. Add the tofu cubes and gently toss them until they're coated in the marinade.
Marinate the tofu for at least 30 minutes, gently stirring the pieces occasionally to recoat them with the marinade (Note 2).
Preheat the oven to 400°F and line a baking sheet with parchment paper. Arrange the tofu cubes on the baking sheet, spooning any excess marinade over them.
Place the baking sheet into the oven. Bake the tofu for about 30 minutes, until the pieces have shrunk slightly and darkened in color.
While the tofu bakes, cook the rice according to the package directions and prep your carrot, cucumber, and avocado. Cut your nori sheets into squares.
To make the dressing, stir the mayo, sriracha sauce, and rice vinegar together in a small bowl.
To assemble, divide the rice among three bowls. Top each bowl with baked tofu, julienned carrots, sliced cucumbers, avocado, and nori squares. Drizzle each bowl with sriracha mayo (Note 3), then sprinkle with scallions and rice seasoning or toasted sesame seeds. Serve with soy sauce or salt to taste.