Sprinkle the salt all over the tofu block. Place 3 kitchen paper on a plate and place the tofu on them. Place another 3 kitchen paper, folded in half on the tofu, and weigh that down with another plate. Like a sandwich. Place a small weight over the plate, like a can of food. Leave aside to drain for 20 minutes.
Add all the sauce ingredients into a small saucepan and leave aside on a cool hob.
Grate the daikon and give it a slight squeeze with your fingers to get rid of some of the liquid, still leaving it moist though, just not dripping. Set aside.
Slice the spring onions (scallions) and set aside.
When the 20 minutes are up, heat the oil in a small wok, on medium high heat, making it come up to 2.5cm (1").
Turn the heat on low under the dashi sauce, cover, and leave to simmer while you get the tofu done.
Pat dry the tofu and cut up into 12 little cubes. Take a kitchen paper and VERY gently dab the tofu pieces, without squashing them.
When the oil is hot enough (throw in a small piece of spring onion, if it sizzles and rises up immediately, the oil is hot enough), dip the tofu pieces into the potato starch, shake off excess and slowly lower into the hot oil. Do this in 2 batches, one tofu piece at a time. Fry the tofu for about 1 minute, turning them gently with a small spatula or chopsticks to ensure that they are cooked all over. Don't brown the tofu. They should still be very light in colour.
Drain on a kitchen paper lined plate and keep warm. Just place them on a cool hob, making sure the kitchen paper doesn't catch fire! Do the second batch.
When all the tofu pieces are cooked, divide them up into 4 small bowls and spoon the hot dashi sauce all over them. This is when the tofu will take on a little colour, which is why in the images here, they are a very light brown. Divide the sauce up equally.
Take a small amount of the grated daikon and place over the tofu, somewhere in the middle. Sprinkle the other garnishes that you are using all over. Serve immediately while still warm/hot.
Th total time does not include the time it takes to drain the tofu, as that is "hands off" time.