Preheat the oven to 375 degrees F (190 degrees C). Spray a 6-well donut baking pan really well with cooking spray.
Whisk the All-Purpose Flour (1 cup), Caster Sugar (1/2 cup), Baking Powder (1 teaspoon), Raw Cocoa Powder (1 tablespoon), Ground Cinnamon (1/2 teaspoon), and Salt (1 pinch) together in a bowl.
Set up a stand mixer with the paddle attachment and combine the Milk (3 tablespoon), 2 tablespoon juice and 1 teaspoon zest from the Lime (1), Olive Oil (2 tablespoon), Tequila (1 tablespoon), and Egg (1). Beat them together thoroughly, then slowly pour in the dry ingredients until you have a lovely batter.
Transfer the batter to a piping bag and evenly pipe it into the donut pan. Bake the donuts for about 15 minutes, until puffy and golden around the edges.
Take them out and let them cool for 30 minutes.
Stir the Powdered Confectioners Sugar (1 cup), Juice from the Lime (2), and Water (1/4 cup) together in a bowl. Dip each donut in the glaze to submerge half of it, then put the donuts on a plate with the glazed side up.
Sprinkle them with the Sea Salt (to taste) on top, then serve and enjoy! They also keep well for a day sealed up.