In a large mixing bowl, add the ingredients for the dressing and whisk well to combine.Add the diced red onion and allow it to sit in the dressing while you prepare the salad ingredients. (5-10 minutes)
Add the rest of the prepared salad ingredients and toss, making sure that the kale and lentils are fully coated in the dressing. Serve chilled.Best eaten within 2-3 days.