To make the dough, combine the flour and salt in a medium bowl. Gradually add the warm water, mixing until a shaggy dough forms. Transfer to a floured surface and knead for 8 minutes until smooth and elastic. Cover the dough with a damp cloth and let it rest for 30 minutes.
While the dough rests, prepare the filling. In a large bowl, combine the ground chicken, chopped onion, minced garlic, grated ginger, soy sauce, sesame oil, cilantro, green onions, and black pepper. Mix everything together until well combined.
Divide the rested dough into 24 equal portions and roll each into a small ball. On a lightly floured surface, roll one ball into a thin 3-inch (8 cm) circle. Try to keep the edges thinner than the center.
Place about a tablespoon of the chicken filling in the center of the dough circle. Fold the wrapper in half to create a half-moon shape. Pinch the edges together and create small pleats along the seam to seal it securely. Place the finished momo on a tray lined with parchment paper and cover with a damp cloth. Repeat with the remaining dough and filling.
Prepare your steamer by lining the basket with parchment paper or cabbage leaves. This prevents the momos from sticking. Arrange the momos in the basket, leaving about an inch of space between each one to allow for even cooking.
Bring water to a rapid boil in a pot that fits your steamer basket. Place the basket over the boiling water, cover with a lid, and steam for 12 to 15 minutes.
The momos are done when the wrappers appear slightly translucent and feel firm. For safety, check that the internal temperature of the chicken filling has reached at least 160°F (71°C) with a digital thermometer.
Carefully remove the momos from the steamer. Serve them hot with your favorite dipping sauce.