Preheat oven to 250 degrees F (120 C), and line two large baking sheets with parchment.
In a small bowl combine the 1 ½ tablespoons tahini, 1 tablespoon mustard, 2 teaspoons vinegar, 1 tablespoon nutritional yeast, and pinch of salt. Whisk together with a fork. The consistency will be thick and paste-like.
Wash and dry the kale. Remove stems and cut into pieces approximately 3 x 3 inches. Irregular shapes are fine, too. *Having smaller, similar-sized pieces helps the kale dry more uniformly. But if you are short on time and don't want to cut/tear into pieces, the leaves can be left whole (after stems are removed; see photo). Increase bake time by 5 to 10 minutes.
Use your hands to massage the cheesy sauce into the kale. A thin coat is best. Place kale on the prepared baking sheets in a single layer. Pieces that are overlapping won't dry.
Bake for about 20 minutes or until the kale is dried and crispy. Serve right away, or cool completely before storing.
Store kale chips in a container (with the lid not quite fully closed) for up to 3 days.