In large bowl, combine flours and water. Knead 15 minutes, adding more flour to water to create a smooth, pliable dough. Cover dough tightly with plastic wrap and let rest for 20 minutes.
Heat sherry in wok over medium heat. Stir-fry onion and cabbage until limp. Add remaining pot sticker ingredients. Cook, stirring for 2 minutes. Remove mixture from heat and place in colander to drain excess moisture.
Divide dough into 24 small balls. On a lightly floured board, flatten each ball of dough into a 3-4 inch circle. Fill each circle with about 1 T filling. Fold circle into half moon shape; pinch edges to seal.
Lightly coat two large nonstick skillets (or work in batches with one skillet) with vegetable cooking spray. Set over medium heat. When hot, add pot stickers, seam side up, flattening slightly on the bottom. When the bottoms of pot stickers are golden brown, add 1/2 C water per pan. Cover and steam for 20 minutes.