Add the quinoa and water to a small saucepan and simmer for 15 minutes. Cover and remove from heat; let sit 5 minutes.
In a small mixing bowl, combine the cooked quinoa, tomatoes and cucumbers. Cover and refrigerate at least 30 minutes.
Meanwhile, prepare the vinaigrette by mixing together the lemon juice, vinegar, shallot, garlic, and mint. Whisk in the olive oil. Season with sea salt to taste.
Just before serving, sprinkle the kale with a little sea salt. Massage the salt into the kale for 2-3 minutes, or until the kale softens. Stir the kale, almonds, and feta (if using) into the tabbouli. Pour the dressing over the salad and mix to combine.