Add the onion and garlic cloves to the bowl of a food processor and pulse just until they are finely minced. Remove the mixture and set it aside.
Add the chickpeas, parsley, coriander (cilantro), salt, chilli powder, chilli, spinach, lemon juice, turmeric and cumin to the bowl of the food processor and pulse until they are roughly blended but not puréed.
Return the onion mixture to the food processor, along with the baking powder and just enough flour so that when you pulse the processor, the mixture begins to get sticky.
Transfer the falafel mixture to a bowl, cover it with plastic wrap and refrigerate it for 1 hour.
Once the falafel mixture has chilled, use a spoon to form the mixture into balls (roughly 1 tablespoon per ball). You can also add additional flour at this point, if the mixture is too wet to scoop.
Set a large pan over medium heat and add a liberal amount of coconut oil so that the pan is well-coated. Let the pan pre-heat, then add the falafel one by one, browning them on the first side for a few minutes, then flipping them once and browning the second side until the mixture is cooked throughout.
Transfer the falafel to a paper towel-lined plate and season them with salt. Repeat this process until you have cooked all of the falafel.
Place three or four falafel inside a halved, warmed pita and drizzle with a tablespoon of hummus, salad leaves and tomatoes.