For this dish it's totally fine to use canned chickpeas. To make this puree you have to peel the chickpeas. I've always done this by hand, which is super annoying but worth it.
That said, I recently found this little video that makes peeling each chickpea by hand a thing of the past.
2 cans of chickpeas
3/4 cups olive oil
1 1/2 cups water
3 cloves of garlic
1 Tablespoons salt
Peel your chickpeas.
Peel and slice your garlic in half. Confit the garlic by gently simmering it a small pot with the oil until the garlic looks barely gold and not fully raw - about 8 minutes. Do this over medium low heat so you don't burn the garlic.
In a blender, puree the chickpeas with the water and salt until smooth. Add the garlic and oil, and puree again. Depending on your blender you may need to do this in batches. You are looking for a constancy