Put the dried chickpeas in a large bowl, cover with enough water (the chickpeas will double in size!) and let them sit covered overnight. The next day, drain and rinse the chickpeas. Cook them until soft. I've used my instant pot and used the 'beans' setting.
Pre-heat the oven to 400°F/200°C.
Add all the ingredients for the falafel patties into a food processor and process until combined.
With the chickpea mixture, form 4 patties. If the falafel mixture does not stick together enough, add more chickpea flour, if it's too dry, add a splash of water or more oil.
Put the falafel patties on a baking tray lined with parchment paper and them spray/brush with oil. Bake them in the oven for about 25 minutes flipping them halfway through.
Peel and pit the avocado, put the avocado flesh in a food processor. Add the salt, lime juice, and ground pepper. Process until it's a smooth sauce. Taste and add more salt or lime juice to taste.
Slice the Burger Buns open. Add the Falafel patty*, avocado sauce, spinach and arugula and top it with the top of the burger bun. Enjoy!
*To re-heat leftover falafel patties, simply pan-fry them to make them warm again.