Pour 1/4 cup water into a small bowl and whisk in the masa or masa harina until thoroughly blended. In a medium (3-quart) saucepan, bring the salsa to a boil over medium-high heat. Strain in the masa mixture, and whisk until the mixture thickens slightly. Remove from the heat and let the sauce cool to room temperature.
Scoop the chicken into a bowl and stir in the thickened salsa. Taste and season with more salt if you wish.