Combine cornstarch and 2 tablespoons pineapple-orange juice in a small saucepan; stir until smooth. Add remaining pineapple-orange juice, ginger, honey, and lemon juice; stir well. Cook over medium heat until thickened and bubbly, stirring frequently. Remove from heat, and transfer to a small bowl. Cover and chill.
Stir in yogurt just before serving. Serve with fresh fruit.