For the mousse: Gently warm the almond milk in a small saucepan. Add the chocolate and cook, stirring, until melted. Remove from the heat and set aside to cool to room temperature.
In a blender, add the cocoa powder, agave, chile de arbol, vanilla, salt and avocados, and puree until silky smooth. With the motor on low speed, slowly add the melted chocolate mixture until fully incorporated. Pour the mixture into a large bowl or individual glasses or ramekins, cover with plastic wrap and refrigerate for at least 2 hours.
For the whipped cream: Meanwhile, add the cream and agave to a large mixing bowl and whisk until lightly thickened and holding soft peaks. Mix in the mezcal and refrigerate until ready to use.
Serve the mousse with dollops of the whipped cream.