Shred zucchini (leave skin on) and onion and let sit 10-15 minutes. Squeeze out the moisture.
Meanwhile, in a medium bowl, combine mayo, Old Bay, parsley, mustard, Worcestershire sauce, and eggs and mix thoroughly.
Toss zucchini and onion in egg mixture and add baking powder. Then add cracker crumbs and stir to combine.
Scoop 1/4 cup of mixture onto a lightly oiled skillet on medium low and flatten slightly. Cook 3-5 minutes or until golden brown, flip and cook an additional 3-5 minutes. Remove from heat. Serve on crackers with tartar sauce or lemon (optional).