In a medium bowl, whisk together all the ingredients for the dressing. Transfer to the fridge to keep cool.
Place 2 serving plates into the fridge to keep cool.
Bring a large pot of water to a boil. Reduce the heat to medium. Carefully add the corn. Cover with a lid and cook for 4 minutes. Remove the corn from water and set aside to cool for 20 minutes. Lay the corn flat on the chopping board, cut the kernels off one side. Rotate and cut the other sides. Discard the cob and transfer to corn to a small bowl. Transfer to the fridge to keep cool.
Bring the pot of water back to a boil. Add shrimps and do a quick stir. Cover and remove from heat. Check the shrimps after 1 – 2 minutes. When the shrimps are no longer translucent, they are ready. Drain and transfer to a plate to cool completely. Once cooled, transfer to the fridge to keep cool if not using immediately.
For the egg crepe, whisk the eggs with sugar and salt. In a large skillet over medium heat, add ½ tablespoon oil. When the pan is hot, add the beaten eggs and tilt the skillet to spread the eggs evenly. Cook for 2 minutes until set, then cover with a lid for 1 more minute, or until cooked. Remove from skillet and cool for 5 minutes. Roll and thinly slice into strips. Set aside to cool completely.
Bring a large pot of water to a boil. Prepare a large bowl of ice water and set aside. Add noodles and separate them immediately with chopsticks or tongs. Cook according to package directions. Drain and soak the noodles into the prepared ice water. Soak for a few minutes, until the noodles feel cold. Drain again. Divide them into 2 serving plates (ones in the fridge).
To assemble, grab a handful of each topping and place on top of the noodles. Top with some radish sprouts if using. Squeeze a small dollop of hot mustard paste on the side of the plate if using. Pour 4 – 5 tablespoons of dressing over each plate. Serve immediately with a bowl of dressing on the side.