Rinse 1 cup quinoa; toast in a saucepan over medium-high heat, stirring, 4 minutes. Add 1 1/2 cups water. Bring to a boil; reduce the heat, cover and simmer 13 minutes. Whisk 2 tablespoons olive oil with 1 teaspoon each whole-grain mustard and red wine vinegar in a large bowl; add 4 thinly sliced celery stalks and 2 tablespoons each chopped red onion, kalamata olives and parsley. Season with salt. Add the quinoa; toss.