Make the chicken filling: In a medium-size bowl, toss shredded cabbage with 3 ½ tablespoons salt and let sit for up to 10 minutes. Drain liquid and dry cabbage and set aside. In a large bowl combine chicken, scallions, cilantro, ginger, garlic, red pepper flakes and strained cabbage. Mix until combined and set aside while you prepare the zucchini.
Assemble the dumplings: Preheat the oven to 350 degrees and line a baking sheet with parchment paper. Using a mandolin or a very sharp knife, slice the zucchini lengthwise. Arrange the zucchini strips (four per dumpling) in a + shape and then an X shape over the cross. Cover with lemon juice to keep from browning as you assemble the dumplings. Place 1 ½ tablespoons of filing in the center and wrap the zucchini strips around the filling to cover completely. Repeat until all filling is used up and bake for 15-20 minutes until the zucchini is golden and firm. Serve with rice vinegar and soy sauce.