Cut the tofu into 2-3 cm pieces. Wrap in paper towel and weigh down with a dish to drain for at least 15 minutes.Cut the green onion finely, and grate the daikon.
Pour the sauce ingredients into a saucepan and bring to a boil, then turn off the heat.
Coat the tofu pieces lightly in potato starch, brushing off the excess. Heat oil to 360F in a deep fryer or medium saucepan, or over medium-high if pan-frying. Deep-fry until crispy and slightly golden, or pan-fry for about 1 minute per cube face. If deep-frying, make sure to drain on a rack or paper towel-lined plate before dishing up.
Place tofu in shallow serving dishes, top with grated daikon, green onion and a sprinkling of shichimi tougarashi, and drizzle with sauce until almost halfway up the tofu blocks. Enjoy!