Combine the quinoa and 2¼ cups of water in a medium-size saucepan. Bring to a boil over high heat. Lower the heat to a simmer, cover, and cook for 15 minutes, or until all the water has been absorbed. Remove from the heat, but keep covered while you prepare the rest of the recipe. Prepare the dressing: In a food processor or blender, combine the pitted and skinned avocado half, shallot, cilantro, vinegar, salt, pepper to taste, and three tablespoons of water. Blend until smooth and creamy. If the dressing is too thick, add a little water, a teaspoon at a time. This makes about ¾ cup of salad dressing.