Prepare bulgur according to package directions (typically soak in hot water until tender, 10–15 minutes). For quinoa, rinse and simmer 15 minutes, then fluff. Let cool—warm grains will wilt herbs.
In a small bowl, whisk olive oil, lemon juice, lemon zest, garlic, oregano, salt, and pepper. Taste. If it doesn't make you smile, add a pinch more salt or lemon.
Dice cucumber, halve tomatoes, mince red onion. Finely chop parsley and mint so they distribute like confetti.
Pat them dry. This keeps the salad from getting watery and helps the dressing cling.
In a large bowl, combine cooled bulgur/quinoa with chickpeas, cucumber, tomatoes, and onion. Pour in half the dressing and toss thoroughly.
Fold in parsley and mint. Add more dressing until everything is glossy but not soupy.
Sprinkle in feta and pistachios. Toss gently so you keep some chunky bits for crunch. Adjust salt, pepper, and lemon to taste.
Eat immediately or chill 20 minutes to let flavors mingle. If adding avocado or arugula, fold them in right before serving.