Preheat your oven to 400°F.
Rinse and drain 1 can of the chickpeas and place them on a paper towel, drying them off well. Place the chickpeas into a large bowl, removing any of the loose skins that come off, and toss with 1 tablespoon of olive oil. Spread them onto a large pan, being careful not to over-crowd them, and sprinkle with salt and pepper.
Bake the chickpeas for 20 minutes, stir, and then bake an additional 5-10 minutes until very crispy.
Once the chickpeas are roasted, transfer them into a large food processor and process until broken down and crumbly. Don't turn them into flour, as you want to leave some texture. Place into a small bowl and set aside.
Heat the remaining 1 1/2 tablespoon of olive oil in a large pan on medium-high heat. Add in the onion and garlic and cook until lightly golden brown, about 2 minutes. Add in the chopped cauliflower and cook an additional 2 minutes, until the cauliflower is also golden.
Turn the heat down to low and cover the pan. Cook until the cauliflower is fork tender and the onions are golden brown and caramelized, stirring every so often. This takes about 3-5 minutes.
Transfer the cauliflower mixture into the food processor. Drain and rinse the remaining can of chickpeas and add it into the food processor, along with the salt and a good pinch of pepper. Blend until smooth, and the mixture starts to turn into a ball, stopping to scrape down the sides as necessary.
Transfer the cauliflower mixture into a large bowl and add in 1/2 cup of the roasted chickpea crumbs (you don't use all of the crumbs, but it's easier to break them down when you have a larger amount.) Stir until well combined.
Pour just enough oil to lightly cover the bottom of a large pan and heat on medium heat. Cook the patties until golden brown, about 2-3 minutes, flip and cook again. It's easiest to cook a few at a time, and work in multiple batches.
Top with hummus, green onion and DEVOUR