Arrange chicken thighs in a single layer in 13 x 9-inch baking dish. In a medium bowl, mix together salsa, honey, soy sauce, mustard, orange juice, olive oil, and ginger root. Pour over chicken thighs. Turn thighs to coat both sides with marinade. Cover and refrigerate for at least 4 hours or overnight.
Bake chicken and sauce, covered, in a 400° oven for 40 minutes. Transfer chicken thighs to a serving platter and keepwarm. Carefully pour sauce into a small saucepan. Bring to a boil over medium-high heat. Mix cornstarch with 2 tablespoons water until smooth. Add to sauce and stir until mixture thickens, about 1 minute. Pour thickened sauce over chicken and serve immediately.