1. Make dressing: place all dressing ingredients into a bowl and blend with an immersion blender until smooth. The sauce will be light green with a few tiny flecks of green leaves. If the sauce is too thick, add extra citrus or a tablespoon of water. Too thin? Add an extra couple scoops of mayo. Tip: use a personal blender if you don't have an immersion blender. The smaller size will ensure everything blends well. 

2. Build sandwich: Toast bread if desired. Spread hummus on both sides to seal in the juices. Then layer cucumbers on one side, and mozzarella on the other. Top with spinach and green goddess dressing. Slice & enjoy!