01 - In a mixing bowl, whisk 2 tablespoons olive oil, juice and zest of 1 lemon, 2 minced garlic cloves, 1 tablespoon each of parsley, oregano, and thyme, 1/2 teaspoon salt, and 1/4 teaspoon black pepper. Add the chicken breasts, coat thoroughly, cover, and refrigerate for at least 15 minutes or overnight.
02 - In a medium saucepan, bring 2 cups water or broth to a boil. Add 1 cup rinsed quinoa, reduce heat to low, cover, and simmer for 15 minutes or until all liquid has absorbed. Remove from heat, fluff with a fork, and let cool completely.
03 - Preheat a grill or grill pan over medium-high heat. Cook the marinated chicken for 6 to 7 minutes per side until fully cooked and juices run clear. Allow chicken to rest for 5 minutes, then slice.
04 - In a large bowl, combine cooled quinoa, cherry tomatoes, diced cucumber, chopped red onion, feta cheese if using, chopped parsley, and chopped mint.
05 - In a small bowl, whisk together 3 tablespoons olive oil, juice of 1 lemon, 1 teaspoon Dijon mustard, 1 minced garlic clove, 1/2 teaspoon honey, and salt and pepper to taste until emulsified.
06 - Pour the dressing over the quinoa mixture and toss gently to coat all ingredients evenly.
07 - Top the salad with sliced grilled chicken and serve immediately, or refrigerate until ready to serve.