Bring 3 cups of water or chicken stock to a boil. Add 1½ cup rice and a tablespoon of butter and add a lid. Allow the rice to cook on medium low heat until the water is absorbed, about 15 to 20 minutes.
Heat the olive oil in the skillet on medium high heat. Add the ground chicken (as well as some salt and pepper to season) and cook through, about 5 to 7 minutes. Chop it into small bits and stir occasionally as it cooks. Drain the grease.
Add chopped onions, garlic and ginger and allow the mixture to simmer about 3 to 4 minutes.
Make the sauce by whisking the Hoisin sauce, soy sauce, and rice. Pour it over the chicken and onions and allow it to cook another 3 to 4 minutes, stirring occasionally.
Finally, add most of your scallions, reserving some for garnish. Add chopped water chestnuts and cook another minute.
To serve, place a scoop of rice in a bowl and top with a scoop of hoisin ground chicken. Garnish the rice bowl with scallions and sesame seeds.