Strip the kale leaves off the kale and rinse. Create a V shape, with your hand by separating your thumb and first finger. Place the kale stem into the V and you should be able to easily pull the leaves from by sliding the stem through the V. Rip the leaves into small to medium sized pieces. Use a salad spinner to dry. Alternatively, you can put the torn leaves in a Ziploc with a few tablespoons of olive oil to coat.
Spread the leaves out on a cookie sheet and lightly coat with olive oil, using a tongs to distribute the oil. It’s best to cover the pan in a single layer rather than heaping too much on at one time.
Place the cookie sheet in the preheated oven. Set the timer for about 5 minutes and take the kale out. Use a tongs to turn the kale a few times so that it is evenly coated with the olive oil and so that it doesn't burn. Use your sense of smell and if you smell it burning take it out and turn it again.
Turn a few more times until it is crispy but not burnt. The cooking time will be about 15-20 minutes total depending on how much kale you put on the baking sheet and how your oven distributes the heat. Sprinkle with a good quality sea salt to taste.
You can think of the crispy kale as yummy green potato chips!