Preheat the oven to 350 and line a large baking sheet with parchment. Use a flexible spatula (or your hands) to combine the oats, sugar and salt, making sure that the brown sugar is completely broken up and there are no lumps.  Add in the tahini and water and stir until a sticky dough forms.

Scoop the dough into even, heaping, golf ball sized mounds onto your baking sheet (all of the cookies fit on one sheet for me) and then use your hand to gently mush each blob into a 2-inch round.  Bake the cookies for about 10 minutes until the edges just barely begin to brown – the cookies will look under-baked.

Leave the cookies on the baking sheet for about 10 minutes to set and then remove them to a rack to cool completely – they will crisp up as they cool.  We wiped these out in an afternoon!