In a small bowl, pour ½ tsp salt over diced cabbage and let sit for 20 minutes. After 20 minutes, drain bowl of water and use cheesecloth or sturdy paper towel to squeeze out excess water.In a medium bowl, mix the pork, cabbage, ginger, garlic, 1 tsp sesame oil, salt, sugar, and green onions with clean hands or fork and spoon. Mix until well combined.Keep wrappers on a clean, dry surface with a damp towel over them. Have a small bowl of water to dip your finger in. Take one wrapper and scoop ½ tbsp pork mixture onto the wrapper. Wet the edges of the wrapper with your finger and the water from the bowl.Fold the wrapper in half and begin pleating. Starting at the side or middle is fine.Pleat only one side of the wrapper, then press onto the other side to seal.In a nonstick skillet on medium high heat, place the dumplings pleat-side up in a circle, making sure none touch so they don't stick together. Pour in the â…“ cup water and place a tight fitting lid on the skillet. Let steam for 2-3 minutes. The dumplings should be a little translucent. Leave lid off.Pour in the 2 tbsp sesame oil and cook until the bottoms of the gyoza are nicely browned, about 2 minutes.