Peel and slice radishes into matchstick pieces. Place pieces in a colander and toss in salt.
While the radishes sit, whisk together the sesame oil, vinegar, lemon juice, and garlic.
Pour radishes and brine in a small jar, close, and shake until all radish pieces are coated.
Let them sit in the refrigerator for at least 1 hour.
In the meantime, combine the spinach, beets, and quinoa in a serving bowl.
Top with marinated radishes and a sprinkle of the brine, serve, and enjoy!