Grate the daikon into a fine mesh sieve, pressing on the grated daikon to squeeze out as much liquid as you can. Set the daikon aside.
To make the dressing, whisk together the ginger, rice vinegar, soy sauce, sugar and salt.
Bring a pot a pot filled with about 3 quarts of water to a boil. Prepare a bowl of ice water.
Remove the skin and any bones from the salmon and cut into bite-size pieces, I cut mine into .5 in x 1.5 in x 1.5inch pieces.
Put the salmon in a tray in a single layer and then add half the potato starch into a small fine mesh sieve (such as a tea strainer). Tap to dust the salmon evenly with potato starch. Flip the salmon over and repeat with the remaining starch.
When the water comes to a boil, add the salmon all at once and then give it a quick stir. Boil for 20 seconds and then turn off the heat. Let the salmon poach for about 2 minutes or until it flakes easily.
Transfer the salmon to the ice water using a slotted spoon and chill.
When the salmon has chilled transfer the salmon to a wire rack lined with a few sheets of paper towels.
Add the salmon to the dressing along with the sesame seeds. Toss to coat evenly.
Plate the salmon and then add the grated daikon to the remaining dressing in the bowl and stir to evenly combine. Mound the seasoned daikon atop the salmon and then garnish with chopped scallions or fresh sprouts (I used broccoli sprouts) and some extra toasted sesame seeds.