Preheat the oven to 375 degrees F. Butter a 9-inch pie dish.
In a medium saucepan, bring the orange juice and 1/2 cup water to a simmer over medium-high heat. Mix in the quinoa. Reduce the heat to medium-low. Cover and simmer until the liquid is absorbed and the quinoa is tender, about 15 minutes. Turn off the heat and allow the quinoa to stand, covered, for 10 minutes. Cool and fluff with a fork.
Unroll the crust and place it in the prepared pie dish. Trim off any excess dough.
In a food processor, blend the powdered sugar, vanilla, eggs, ricotta and orange zest until smooth. Add the cooked quinoa and pulse once to incorporate.
Pour the filling into the prepared pie dish and bake until the outside of the filling is set but still a little loose in the center, 30 to 40 minutes. (If the crust begins to darken too much after 20 minutes of baking, cover the edge of the crust with a strip of aluminum foil.)
Cool to room temperature, at least 1 hour. (The filling will set as it cools and may crack in places.) Cut into wedges and serve.