Cook the pumpkin in a medium saucepan of boiling water for 8 to 10 minutes, until soft. Drain and mash. Set aside to cool.
Sift the rice flour, cornstarch, and xanthan gum into a large mixing bowl (or mix with a whisk to ensure they are well combined). Add 2 tablespoons of the chives, feta, mashed pumpkin, eggs, and cumin, and mix well. Season with salt and pepper.
Heat 1 tablespoon of the oil in a medium nonstick skillet over medium heat. Add 2 heaping tablespoons batter per fritter and cook for 2 to 3 minutes. Flip over and flatten slightly with
the back of a spatula, then cook for an additional 2 minutes or until golden brown and cooked through.
Transfer the fritters to a plate and cover with foil to keep them warm if eating immediately (otherwise store them in the fridge for later). Repeat with the remaining oil and batter until
all the fritters are cooked.
Mix together the sour cream and remaining 1 tablespoon of chive. Serve the fritters with salad, if desired, and a dollop of the sour cream topping.