Quinoa Tabbouleh Salad

Name: Quinoa Tabbouleh Salad
Ingredients: 1 cup uncooked quinoa ((see notes)); 2 cups water or vegetable broth (for cooking quinoa); ½ teaspoon salt ((or more, if using unsalted water or stock)); ½ yellow or red onion (finely diced); 2 garlic cloves (minced); juice and zest of 1 lemon ((about 2 tablespoons lemon juice, see notes)); 1 large tomato ((or 2 plum tomatoes)); 1 large cucumber; 2 tablespoons olive oil; 1 cup fresh parsley leaves (finely diced); ¼ cup fresh mint leaves (finely diced (optional)); salt & pepper (to taste)