Preheat oven to 375 degrees. Place beets in a roasting pan. Add enough water to barely cover them. Seal pan with a lid or foil. Roast beets 40 minutes, until tender. Remove from oven; let cool.
Place cabbage and daikon in a large bowl and sprinkle with 1½ teaspoon sea salt. Toss, massaging with your hands, to soften a bit; set aside.
When beets are cool enough to handle, slip skins off with your fingers and cut into fourths, lengthwise.
Whisk vinegar, honey, olive oil and ½ teaspoon pepper in a small bowl; season with a pinch of sea salt. Drizzle over cabbage and daikon. Add roasted beets, toss to combine; and serve.