In a small, heavy saucepan, melt 1/2 cup of the sugar with the water over high heat. Cook, without stirring, until mixture is a caramel color and is fragrant. Do not let it get too dark or it will taste bitter.
Very carefully pour the caramel into the bottom of a 1 qt flan mold or 6 caramel cups. Swirl quickly to coat the bottoms and sides.
Preheat the oven to 350 degrees F.
Place almonds into a food processor with 1/4 cup of the remaining sugar and process until finely ground. Set aside.
In a bowl, whisk together the egg yolks and remaining sugar. Add the orange juice, zest almonds and mix well.
Pour the mixture in to your prepared baking mold or cups and place into a larger baking pan. Add hot water to the pan to reach halfway up the sides of the mold or cups. Cover the baking pan with aluminum foil.
Bake until a knife inserted into the center emerges clean, 35-40 minutes for the custard cups and 1 hour for the mold. Remove from the oven, then remove from the baking pan. Let cool a bit then cover with plastic wrap and refrigerate until well chilled.
To serve, run a thin knife around each flan and invert onto individual plates or one large plate. Spoon the caramel that flows onto the plates over the top. Garnish with orange segments.