Whisk together the flour, salt, baking soda and cinnamon and set aside.Toast the walnuts for a few minutes on medium-low heat in a dry pan until fragrant and crisp. Remove from the pan and set aside. Cream the butter and sugar for three minutes until light and fluffy. Add the eggs, one at a time and mix until incorporated, then add the vanilla. Use a rubber spatula to scrape butter down from the sides of the mixing bowl.Add the dry ingredients to the butter mixture, a spoonful at a time, until it is just incorporated. Mix in the oats, then add the nuts and the coconut flakes. I usually have to switch to a rubber spatula and mix it by hand at this point because the dough becomes very thick. Use a 1 ounce ice cream scoop to scoop out uniformed dough balls onto a sheet pan lined with parchment paper or a baking mat. If there are bits of coconut sticking out, just press them into the dough with your finger.Bake the cookies for 11 minutes at 350 degrees. Allow them cool for a few minutes before handling, then bake the next batches.