In a medium bowl sift flour and salt together; set aside.
Mix butter on medium speed in a stand mixer with a paddle attachment or with a hand mixer until fluffy, about 2 minutes. Add sugar; mix until smooth, then add egg and vanilla, mix until smooth.
Add flour mixture and on low speed mix until just combined. Add the dough to a large sheet of plastic wrap and form into a cylinder about 2 and a half inches in diameter, packing the dough firmly and evenly together. Wrap well with plastic wrap and freeze 2 hours or overnight.
Preheat oven to 350 degrees F. Line baking sheets with parchment.
With a sharp knife cut the cookie roll into 1/4 inch slices, place on baking sheets and bake, in batches, about 12 minutes or until edges are lightly golden. Remove to cool on wire racks.
In the meantime, to make the coconut caramel layer, preheat oven to 300 degrees F. Spread coconut evenly on a parchment-lined baking sheet (preferably one with sides) and toast 5-10 minutes or until coconut is golden. Remove and allow to cool.
Place the unwrapped caramels in a microwave safe bowl with milk and salt. Cook on high for 3-4 minutes, stopping every minute to stir the caramel When completely melted stir in toasted coconut.
Immediately spread the coconut over the tops of each cookie from edge to edge using a small spatula, butter knife or spoon. If caramel gets too firm to work with reheat a few seconds in microwave.
Melt chocolate in a small bowl in the microwave, stirring every 30 seconds until smooth. Dip bottoms of each cookie into chocolate and place top side down on parchment or wax paper. Add remaining chocolate (or melt more if needed) to a piping bag or plastic bag with the corner cut off. Drizzle the tops of each cookie with chocolate. Allow chocolate to set.
Store in an airtight container.