Position a rack in the center of the oven and preheat to 400 degrees F. Grease a standard 12-cup muffin pan, preferably nonstick, with olive oil or coat with cooking spray. Add the quinoa, peas, shredded cheese, green onions, herbs, and chile to a medium bowl and combine well with a fork (if your grains are pre-cooked make sure to separate any clumps). Divide the grain mixture equally among the muffin cups, about 1/3 cup for each, filling until almost full. Add eggs to a large bowl and season with 1/2 teaspoon salt and pepper. (If using previously cooked salted grains and greens only use 1/4 teaspoon salt). Whisk well, until foamy, about 30 seconds. Divide egg mixture into the cups using about 1/4 cup for each. Sprinkle each muffin with about 1/ teaspoon of the finely grated cheese and gently press in 1 olive (if using). Bake until the frittata muffins have puffed up and turn light golden on top and golden brown around the edges, about 20-25 minutes. Transfer pan to wire racke and let cool for about 5 minutes. Using a knife or thin rubber spatula, carefully go around edges of each muffin to gently release from pan. Eat warm or at room temperature.