To prepare the paste, boil the almonds and remove the peel. Once they are cold and somewhat dry, put them in a food processor or a blender and chop them finely.
Put the chopped almonds in a bowl, add the lemon zest, the sugar and egg whites. Mix until the egg whites dilute the sugar and the mixture becomes a paste.
Take a lump of dough, roll it into a stick about 8" long and 1/2" thick. Press with a fork to flatten it and create ridges with the teeth of the fork. Cut the strip of dough with a knife in rhomboid shapes about 1 1/2" long.
Place all the cookies on a baking sheet and bake for 10 mins. at 350F. Let them cool.
Make your icing my mixing the milk and sugar. The icing should be a thick liquid.
With a brush apply the icing on each cookie to cover the top.
Let the icing dry completely for several hours.