Make the Potsticker Dipping Sauce and set it aside so flavors can mingle. Make Hoisin Sauce (for the filling), if needed. Click the links up above for the recipes.
Heat the sesame oil in a large skillet over medium heat. Add the mushrooms and green onions and cook, stirring often, for 2-3 minutes. Add the garlic and ginger and continue to cook, stirring constantly, for 1 minute. Remove from heat and let it cool completely.
In a food processor, combine the ground pork, cooled mushroom mixture, soy sauce, hoisin sauce, black pepper, to taste. Pulse until well combined.
Spread out the potsticker wraps and scoop a small teaspoon full of filling onto the center of each wrap. Wet the top of each potsticker wrap with a baster brush dipped in water. Fold the potsticker to make a moon shape and pinch shut with 4 to 5 pleats along the side. Really make sure they are sealed, so the filling doesn't fall out. Place onto a cooking sheet with a silpat mat or waxed paper. Cover the completed potstickers with a towel to prevent them from drying out.
Heat 1 tablespoon of olive oil in a pan. Once hot, potstickers and cook until the bottoms are golden brown. Add 1/4 cup of water and cover with a lid. Steam for 3 minutes; remove from pan to a serving tray. Repeat with the remainder of potstickers. Remove from heat and serve with a dipping sauce.