In a small skillet, toast the sesame seeds, stirring occasionally, until lightly browned, about 2 minutes. In a small bowl, whisk the lemon juice with the soy sauce, vegetable oil and sesame oil.
In a large bowl, toss the red cabbage with the napa cabbage, carrots and daikon. Add the dressing, season with salt and pepper and toss to coat. Sprinkle with the sesame seeds and serve.
The vegetables and soy dressing can be refrigerated separately for 2 days.