Melt the chocolate and coconut milk in a double boiler over low heat. Mix until you get a smooth texture. Keep warm.
Pour the chickpea water (aquafaba) into a cold bowl and use an electric beater to whip it until it looks like a soft mousse.
Slowly add the brown sugar, one spoon at a time, beating well between each spoonful.
Keep beating until you obtain firm peaks that look like meringues.
Gently whisk ⅓ of the mousse into the chocolate mixture.
Stir in the second third of the mousse and then pour the chocolate mixture into the last third of the chickpea mousse. Fold it gently until a light homogenous texture is obtained.
Divide the mousse between 6 ramekins. Cover with plastic wrap and refrigerate for at least 6 hours bevore serving.