Place chicken and salt in a bowl. Evenly rub salt into chicken. Refrigerate for 30 minutes.

Place a steamer basket into a saucepan and fill with water to just below the bottom of the steamer. Rinse chicken and place into the basket. Bring water to a boil; cover and steam chicken until juices run clear, about 30 minutes.

Heat vegetable oil in a skillet over medium heat. Stir in onion; cook until tender, 3 to 4 minutes. Mix in garlic; cook until fragrant, about 1 minute. Stir in soy sauce and sesame oil, then remove from heat.

Spoon sauce over chicken and garnish with cilantro to serve.