Position racks in the top and bottom of the oven and heat oven to 325 degrees. Line two baking sheets with parchment paper.
In a medium bowl, whisk egg whites, salt and sugar until creamy, thick and white. Whisk in 1 tablespoon of the oil and the vanilla.
Fold in the flaked and shredded coconut and the flour, mixing well so the coconut is evenly moistened. At this point, the macaroons can be baked, but you can also refrigerate the mixture in an airtight container for up to 2 days.
Use a small 1-ounce cookie scoop to portion the coconut mixture (about 2 tablespoons per macaroon) and squeeze together in a ball. Space a few inches apart on the prepared sheets and rough up the texture a little with your fingers.
Bake, switching the pans from back to front and top to bottom, until golden on the bottom and toasty all over, 16 to 21 minutes. Let cool on baking sheets for a few minutes, then transfer the macaroons to a cooling rack close together. Set the rack over one of the baking sheets (keep the parchment on) to catch chocolate drips during drizzling. Cool the macaroons completely.
Melt the chocolate with the remaining 1/2 teaspoon oil in a small saucepan over low heat and stir well. Drizzle the macaroons with the chocolate. Let the chocolate set a little in a cool place or in the refrigerator before topping with flaky salt. The macaroons can be stored in an airtight container at room temperature for up to 1 week or frozen for up to 1 month.