Combine the first 7 ingredients in a medium-sized bowl. Cut the tofu into 24, 1” cubes and set in the bowl. Cover and marinate in the fridge overnight. Arrange an equal amount of the spinach on each of 4 plates. Lift the tofu from the marinade and set 6 pieces in the centre of each plate. Surround the tofu with the carrots, radishes and cucumbers. Drizzle all with some of the marinade, sprinkle with the green onions and sesame seeds, and serve.
Note: Leftover marinade can be stored in the fridge for up to a week and used to flavour stir-fries.