Slice your orange into rounds, they need to be thin. About ¼ inch thick at most. Discard ends and seeds. You can cut the rounds into wedges at this point if you want a different shape.
In a medium, heavy-bottomed pan add the sugar and water. Heat until the sugar dissolves and then add your orange slices and any spices. Bring to a boil over medium-high heat then reduce heat to a slow simmer and cook, uncovered, for 25 to 30 minutes.
Allow the orange slices to cool for a few minutes then transfer to a sheet of parchment so they can finish draining.
To make the chocolate coating, combine cocoa powder and coconut oil. Stir until no lumps remain. The coating should be thick but not stiff, allow to cool if too thin.
Dip the orange slices in the chocolate halfway. Place on parchment to cool. Sprinkle on sea salt. Place the parchment on a baking sheet and cool in the fridge for 15 minutes.
The chocolate coating will taste bitter without the oranges. If you want to sweeten it add maple syrup (or honey for non-vegan).
The oranges can be 24 to 48 hours in advance. Cover and store in the refrigerator,
The chocolate-covered oranges are best served within 24 hours.