In a large bowl, mix the pork, spinach, ginger, thyme, soy sauce, rice wine, sesame oil, and garlic powder together.
Pour a bit of water into a small bowl. You'll use this to dip your potsticker wrappers in. Dip a bit of the wrapper (about 1/2 inch deep), and rotate it so that you get a semi-circle of water. This will help you seal the pleats on the potsickers. Let the potsticker wrapper rest on your fingers on your left hand. Then, you'll fill the center with a spoonful of meat. Resist the urge to fill it with too much filling! It will make the folding more difficult.
Using your right thumb and forefinger, pinch and seal a bit of the dry part of the wrapper with the wet part. Use your left thumb to hold the filling down as you pleat the potsticker. Then, using your forefingers, pinch a bit of the wet part of the wrapper together. You have created your first pleat!
Press down that pleat along the dry side of the wrapper. Continue creating pleats until until you reach the end on the left side. Seal the potsticker. When I'm done folding/pleating a potsticker, I like to set it down on a large tray or baking sheet and use my fingers to make sure that the top of the potsticker is shaped like a half-moon. This is not necessary, but it is just makes the potsticker prettier. Repeat this step for all of the potstickers.
To cook them, heat a large sauté pan with a tablespoon of oil over medium high heat. When the pan is hot, line the potstickers in the pan, bottom side down. Let the potstickers fry for about a minute, then pour about 3 tablespoons of water in the pan and cover it with a lid. Reduce the heat just a little. When the water evaporates, continue adding another 3 tablespoons of water and close the lid. Continue doing this until you have cooked the potstickers for about 6-8 minutes (8-10 minutes if you're cooking frozen potstickers).
Dip the potstickers in soy sauce or chili sauce!