To Cook the Quinoa: Run cold water over quinoa in a fine-meshed strainer until wanter is clear. In a small saucepan, add 1 cup quinoa and 2 cups water. Bring to a boil. Once boiling, reduce heat to a simmer and cover. Simmer 15-20 minutes or until all water is absorbed.
To Make the Dressing: Place everything for the dressing in a small bowl and whisk to combine.
To Make the Salad: Let the quinoa cool to room temperature. Toss the cooled quinoa with the tomatoes and spinach. Pour the dressing over the salad and stir to coat the ingredients with the dressing. Sprinkle the feta and pine nuts over the top and gently toss to combine. Serve immediately, or refrigerate until ready to serve.