In a food processor, grind the almonds with the sugar and orange zest until finely ground. Add the butter and pulse a few times, until the butter is evenly distributed. You may need to stir the mixture with a spatula before placing it in the tart tin. Pat almond mixture into the bottom and sides of tart tin. Bake for 10 minutes, until the nuts are lightly toasted, then remove to a rack to cool.
Fill the tart crusts with the curd. You can decorate it with a curl of blood orange peel or serve as is.