Preheat your oven to 325F (165C) and line a large cookie sheet with parchment paper.
In a large bowl, stir together coconut flakes, condensed milk and vanilla extract until well-combined.
In a separate bowl (make sure that it is completely clean and dry) combine the egg whites and salt.
Using an electric mixer with whisk attachment (you could also use standard beaters if you don't have the whisk attachment, but the whisk is faster) beat egg whites and salt until stiff peaks form (see picture in post for photo of stiff peaks and description).
Gently fold the egg whites into the coconut mixture until completely combined.
Using a 1 ½ Tablespoon-sized cookie scoop, scoop macaroon mixture into balls and drop onto prepared cookie sheet, placing at least 1" apart.
Bake on 325F (165C) for 20-23 minutes or until tops are just beginning to turn golden brown.
Allow coconut macaroons to cool completely before dipping in chocolate (if desired).
To dip in chocolate -- chop chocolate bar into small even-sized pieces and place in a small microwave-safe bowl.
Heat in 20-second increments, stirring in between) until chocolate is smooth and completely melted.
Dip the bottom of each macaroon into chocolate and return to baking sheet for the chocolate to harden.
*Just slightly less than 1 cup**If your eggs are not at room temperature, a quick way to bring them up to temp is to place them in a bowl of warm (not hot!) water and allow them to sit for 15 minutes, then dry the eggs, crack them, and separate the yolks and whites.