Wrap the tofu in a kitchen towel, place it between two sheet pans, and put a heavy weight, such as a cast-iron skillet or canned beans, on top. Press for at least 15 minutes to extract any liquid.
Into a shallow bowl, strain and reserve the liquid (aquafaba) from the chickpeas. (Save the chickpeas for another meal.)
Make the coleslaw: In a medium bowl, toss together the cabbage, carrot, apple, scallion, and parsley. Set aside.
On a large plate, combine the panko, nutritional yeast, onion powder, garlic powder, rosemary, thyme, salt, and a few grinds of pepper and mix well. Place the cornstarch on a separate plate.
Cut the tofu block into 4 slices lengthwise. Coat one tofu slice with the cornstarch, dip it into the aquafaba, and then press firmly into the panko mixture, coating both sides and the edges to get a nice thick coating. Press down again to make sure the coating adheres to the slice. Repeat with the remaining slices.
Line a plate with paper towels. In a cast-iron skillet or heavy-bottomed pan, heat the grapeseed oil over medium heat. When it starts to shimmer, fry the tofu in batches until golden brown, 3 to 4 minutes each side. Remove from the pan and drain on the prepared plate.
Make the dressing: To a high-speed blender, add the lemon juice, olive oil, parsley, garlic, maple syrup, and mustard and blend until smooth.
Toss the coleslaw with half the dressing and drizzle the remaining dressing over the tofu schnitzel. Garnish with the capers and radishes if desired.