Make the Feta Dip:
Whisk together sour cream, feta cheese, dill, black pepper, red pepper, and salt in a medium bowl until feta is smooth, about 1 minute.

Make the Cabbage Fritters:
Combine thinly sliced cabbage, chopped scallions, grated carrot, and kosher salt in a large bowl and stir until well mixed.
Stir in the lightly beaten eggs, all-purpose flour, white rice flour, cornstarch, chopped ginger, crushed red pepper, garlic powder, dried dill, baking powder, baking soda, and ground black pepper until everything is combined.
Heat 2 tablespoons of canola oil in a large nonstick skillet over medium-high heat until it shimmers, about 2 to 3 minutes. Spoon a scant 1/3 cup of the cabbage mixture into the skillet and flatten it evenly with a spatula to about 1/4-inch thickness. Add 3 more fritters to the skillet, spacing them about 1-inch apart, and flatten them as well.
Cook until the fritters are golden brown on both sides, approximately 3 minutes per side. Remove the fritters from the skillet and place them on a wire rack. Loosely cover with aluminum foil to keep them warm.
Repeat this process three more times with the remaining cabbage mixture and 6 tablespoons of oil. Garnish with additional scallions. Serve warm with the Feta Dip.