In a large bowl, combine the grated sweet potato, mashed chickpeas, flour, cilantro, green onions, garlic, cumin, paprika, coriander (if using), salt, and pepper.
Add the egg (or flax egg) and mix until well combined.
Form the mixture into small patties, about 8–10 fritters.
Heat a generous amount of olive oil in a large skillet over medium heat.
Cook the fritters for 3–4 minutes on each side, until golden brown and crispy.
Transfer to a paper towel-lined plate to drain excess oil.
In a blender or food processor, combine the avocado, Greek yogurt, lime juice, garlic, olive oil, salt, and pepper.
Blend until smooth, adding water one tablespoon at a time until the sauce reaches your desired consistency.
Serve the crispy fritters warm with the creamy avocado sauce on the side. Garnish with extra cilantro and lime wedges if desired.