Wash the kale thoroughly and remove the tough center stems. Chop the leaves into thin ribbons (chiffonade) and place in a large salad bowl.
Drizzle 1 tablespoon olive oil and 1 tablespoon lemon juice over the chopped kale. Using clean hands, massage the kale for 2-3 minutes until it softens and becomes darker in color.
Cook quinoa according to package directions (typically 1/2 cup dry quinoa with 1 cup water). Allow to cool completely.
In a small bowl, whisk together the remaining olive oil and lemon juice. Season with salt and pepper to taste.
Add the cooled quinoa, diced cucumber, halved cherry tomatoes, and sliced red onion to the bowl with the massaged kale.
If using optional ingredients, gently fold them in at this stage.
Pour the dressing over the salad and toss gently to combine all ingredients evenly.
Taste and adjust seasoning if needed with additional salt, pepper, or lemon juice.
For best flavor, allow the salad to rest for 5-10 minutes before serving, or refrigerate for meal prep.