Raw kale is very tough, but it can be made much softer and more enjoyable to eat if the kale is handled the right way.  Following the guidance in J. Kenji Lopez-Alt’s book The Food Lab, the tough stems should be removed, the leaves cut into ribbons and then massaged with olive oil and salt at the ratio of 1 Tbs. of olive oil and ½ tsp. of kosher salt per bunch of kale (which will weigh 6-8 ounces).  The kale should be massaged by hand for 2 minutes and then allowed to stand for 15-60 minutes before using. 

The treated kale is then ready to use in a salad, in this case in a Caesar salad with croutons, anchovies, Italian dressing and Parmesan (plus I added some cherry tomatoes and sliced red onion).