In large bowl, whisk together the flour, potato starch, salt, baking powder.
In another bowl, combine water, egg, kimchi.
Whisk the kimchi mixture into the flour mixture -- until smooth.
Fold in vegetables and the scallions.
Heat the oil in large skillet over medium heat.
Spoon and flatten 1/4 cup portions of batter into the skillet, as many as will fit without touching.
Fry 2 or 3 minutes until golden brown. Flip and do the same on the other side.
Transfer to a plate lined with a paper towel.
Serve with a dipping sauce. You can buy Asian dipping sauces at places like Trader Joe's. Or make your own: some combination of coconut amines, soy sauce, etc.