Preheat the oven to 350 degrees F. Beat the eggs in a large bowl. Add the quinoa, spinach, goat cheese and salt and stir to combine. Spray the mini muffin pan with nonstick spray. Fill the mini muffin cups 3/4 of the way full with the mixture, then add an extra dollop of goat cheese and a bit of black pepper on top of each. Bake until golden brown, 7 to 9 minutes. Serve warm.