Cut chicken breasts crosswise into slices. Heat butter in a skillet on medium-high heat. Add chicken. Coat chicken pieces in melted butter, then sprinkle onion salt and pepper over chicken. Stir to coat and continue to cook until chicken is completely cooked. Remove chicken from skillet and set aside.
In same skillet on medium-high heat, melt 6 Tablespoons butter. Add flour, brown sugar, salt, ground ginger, and black pepper and stir into butter to create a roux. Add orange juice concentrate and chicken broth. Whisk until the mixture is smooth and no lumps remain. Continue to whisk or stir until the mixture thickens.
Add cooked chicken to orange juice sauce and stir to coat chicken. Continue to simmer until chicken is warmed again. Add more water if needed to create a flowing sauce. Serve over rice. Garnish with orange slices.