Add split peas and 8 cups water to a large pot and bring to a boil. Once boiling, lower heat to medium-high and cook for 25 minutes, or until peas are slightly tender.
Add diced potatoes to the pot and cook for 15 more minutes.
Drain peas and potatoes and let cool for 10 minutes.
Add peas and potatoes to a large bowl and mash with a potato masher.
Add spinach, chickpea flour, onion, garlic, soy sauce, coriander, cumin, salt, and red pepper flakes and stir to combine.
Form the mixture into 20 small patties.
Add 1 tablespoon oil to a large frying pan and place over medium heat.
Add 8 patties to the pan (or as many as will fit in a single layer) and cook for 3-4 minutes on each side. Repeat cooking process with the remaining patty mixture.