Place the quinoa and water into a small saucepan and bring it to a boil over medium heat. Reduce the heat to low, cover the saucepan, and cook the quinoa for 15 minutes, or until all the liquid has been absorbed. Set the pan aside. 

Preheat the oven to 350 degrees Fahrenheit. Use cooking spray to grease a 12-cup (2.8-liter) Bundt pan. Sprinkle the potato starch over the greased pan and then shake the pan to remove any excess starch.

Place the quinoa in the bowl of a food processor. Add the orange juice, eggs, vanilla, oil, sugar, cocoa, baking powder, and salt and process until the mixture is very smooth.

Melt the chocolate over a double boiler, or place in a medium microwave-safe bowl, and put in a microwave for 45 seconds, stirring and then heating the chocolate for another 30 seconds, until it is melted. Add the chocolate to the quinoa batter and process until well mixed.

Pour the batter into the prepared Bundt pan and bake it for 50 minutes, or until a skewer inserted into the cake comes out clean.

Let the cake cool for 10 minutes and then remove it gently from the pan. Let it cool on a wire cooling rack.

To make the glaze, melt the chocolate in a large microwave-safe bowl in the microwave (see above) or over a double boiler. Add the oil and vanilla and whisk well. Let the glaze sit for five minutes and then whisk it again. 

Use a silicone spatula to spread the glaze all over the cake.