In a large mixing bowl, combine drained and rinsed garbanzo beans and cannellini beans, chopped spinach, canned artichoke hearts, and finely chopped green onion. Mix gently until well combined.

In a separate small bowl, whisk together Greek yogurt and mayonnaise until smooth. Incorporate grated Parmesan cheese, minced garlic, and Italian seasoning. Add lemon zest and a pinch of salt, mixing thoroughly.

Pour the prepared dressing over the bean and vegetable mixture. Gently fold the dressing into the salad with a spatula for 1-2 minutes to coat everything evenly.

Cover the salad and refrigerate for at least 30 minutes to allow flavors to meld. Serve chilled.