Add the mushrooms, garlic, and green onions to the bowl of a food processor and pulse until the mushrooms are a fine crumb, about 15 seconds.
Next, add the soy sauce and panko. Pulse again until the mixture resembles a coarse paste, another 10 seconds.
Fill each of the wonton wrappers with 1-2 teaspoons of mushroom filling.
To seal, dip your finger in water and rub it along the edge of the wrapper.
Bring the corners of the wrapper up to the center and twist them to seal in the filling.
Brush the bottom of each wonton with water and dip it into the sesame seeds.
Heat a large nonstick skillet over medium-high heat.
Add the olive oil and then add the wontons to the pan. Cook for 2-3 minutes or until they are crisp and golden brown on the bottom.
Working quickly, add a small handful of ice cubes to the pan and immediately cover it with a lid. Shake the pan gently and cook for another 2-3 minutes, or until the dumplings are tender.
Remove the dumplings to a plate and garnish with additional green onion and sesame seeds, if desired.
Serve with garlic chili oil and enjoy.
Leftover dumplings can be kept in an airtight container in the fridge for up to two days.