For the vinaigrette: Combine the apple cider vinegar and mustard in a small bowl, then slowly whisk in the olive oil (this step is called emulsifying). Make sure it's fully incorporated. Whisk in the orange juice, honey, garlic powder, salt and pepper, then set aside or refrigerate.
For the salad: Combine the coleslaw mix, kale, almonds, onions and clementines in a large salad bowl. Toss with the vinaigrette and serve.