Cook the onions in 1 1/2 teaspoons of olive oil in a skillet over medium heat until soft and translucent.
Pulse the garbanzo beans, imitation sour cream, cornmeal, garlic, cumin, coriander, salt, and hot sauce in a food processor until smooth. Transfer to a bowl and stir in the onions; cover and chill for 30 minutes.
Place 1/4 cup cornmeal in a shallow dish. Form the garbanzo bean dough into 6 patties, 1/2-inch thick; roll the cakes in cornmeal.
Heat 2 tablespoons of olive oil in a large skillet over medium heat. Cook the falafel cakes until browned on both sides, about 5 minutes per side.