In a small jar or squeeze bottle, combine the olive oil, vinegar, lemon juice, and salt. Secure the lid and shake vigorously to combine. Place the kale leaves into a large salad bowl, add the apples, walnuts, and blue cheese on top of the kale and lightly toss to combine. Dress the salad and lightly toss. For 1 serving at a time, Just prepare it all and assemble before eating each evening.