Pulse the drained chickpeas, onion, garlic, cilantro, parsley, coriander, cumin and lemon zest until it forms a coarse meal.
Sprinkle in the flour and baking soda and pulse a few times to combine, then test the mixture to make sure that it holds together adding more flour until it does.Refrigerate the mixture in a covered container for a few hours.Form the mixture into balls or patties.
Heat oil in pan to 350F/180C, fry the balls in small batches until golden brown, about 4-6 minutes and set aside on paper towels to drain.Assemble sandwich and enjoy!