Very thinly slice the daikon radish into 2-inch-long (5 cm) pieces. Sprinkle with the salt and let sit for 5 minutes. Squeeze out the excess water.
In a medium bowl, combine the lemon juice, vinegar, and sugar, and mix until the sugar is dissolved. Add the daikon and toss. Refrigerate for at least 30 minutes. Garnish with the lemon peel.