Preheat oven to 350 degrees. Spray a 9-inch pie plate with cooking spray.
Place the quinoa on a baking sheet and cook for 10 minutes. Let cool.
Make the flax gel: In a small bowl, combine the ground flax seed with hot water and let sit for 15 minutes.
When the quinoa has cooled, place in a food processor and process for 30 seconds. Add the almond flour, starch, and ¾ teaspoon of salt. Pulse to combine. Add the flax gel and 1 tablespoon olive oil and process until the mixture holds together when pressed. Spread into the prepared pie plate and bake for 5 minutes. Leave the oven on.
Brush the bottom of the tart crust with the mustard. Layer the tomatoes in concentric circles in the crust. Sprinkle with ½ teaspoon of salt, ¼ teaspoon pepper, the basil and chives.
In a mixing bowl, beat the eggs and goat cheese together. Pour over the tomatoes, drizzle with 1 tablespoon olive oil, and bake for 35 – 40 minutes or until the filling is set and the top is starting to brown. Let cool for 10 minutes before slicing. Can be served warm, at room temperature, or cold