Cook the Quinoa: In a medium saucepan, combine the rinsed quinoa and chicken broth (or water). Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes, or until all liquid is absorbed and quinoa is fluffy. Remove from heat and let stand, covered, for 5 minutes, then fluff with a fork.

Cook the Chicken: While the quinoa cooks, heat 1 tbsp olive oil in a large skillet over medium-high heat. Season the chicken cubes with salt and pepper. Add chicken to the skillet and cook for 5-7 minutes, stirring occasionally, until golden brown and cooked through. Remove from heat and set aside to cool slightly.

Prepare the Dressing: In a small bowl, whisk together all dressing ingredients: olive oil, lemon juice, red wine vinegar, dried oregano, Dijon mustard, minced garlic, salt, and pepper. Taste and adjust seasoning as needed.

Assemble the Salad: In a large mixing bowl, combine the cooked and cooled quinoa, cooked chicken, halved cherry tomatoes, diced cucumber, thinly sliced red onion, fresh parsley, and fresh mint.

Dress and Serve: Pour the lemon-herb dressing over the salad and toss gently to combine. If using, sprinkle with crumbled feta cheese just before serving. Serve immediately, or refrigerate for later.