Combine cocoa powder and 1/4 cup of coconut milk in a small saucepan. Whisk well to make a paste.
Slowly add the remainder of the coconut milk and orange zest (if using) whisking vigorously, and heat over medium heat for five minutes. Don't let it boil. Add maple syrup or honey if using.
If you're using orange zest and want a super-smooth texture, you can either blend the mixture in a blender, food processor or use an immersion blender. You can also strain the mixture before stirring.