Mix the chickpea flour and water until completely smooth and without lumps. Note the batter will be very runny, similar to a crepe batter. Cover and let rest at least 2 hours but preferably 5 or overnight.
Remove any of the foam that has formed on the top of the batter. Add the oil and salt.
Preheat the oven to 430° F (220° C).
If you are using a pizza pan with a lip or a cast iron, put it in the oven when preheating (pouring the batter in the hot pan helps it from sticking and creates an extra crispy crust).
If you have preheated your pan, carefully pull it out with pot holders, drizzle a generous amount of olive oil in the pan, swirl it around to coat the bottom and add enough of the batter to make your cecina about ⅛-¼ (3-6 mm) inch in height. Just eyeball it. It might not be perfect the first time but you will get an idea and then do better on the second batch.
If you are using an oiled baking sheet (about 10.5"x15"), pour the batter in, again, being sure the cecina is about ⅛-¼ inch in height. You can also use a baking sheet lined with parchment paper for easy cleanup.
Bake in the bottom of the oven for 10-15 minutes if using the pre-heated cast iron and 15-20 if you are not using until golden brown and crispy on the edges. It’s hard to tell but the middle should still be soft and creamy. I have found that every time I do it, it cooks slightly differently so really keep an eye on the time and check on it if you start to smell a good aroma - it may be close to being done!
Drizzle with more olive oil and finish with freshly ground black pepper before cutting into large wedges.