Bring first 6 ingredients to a boil in a large saucepan over medium heat. Stir in grits; cover, reduce heat, and cook, stirring often, 6 to 8 minutes. Pour into a lightly greased 9-inch pieplate; cool.
Unmold grits, and cut into 6 wedges; lightly brush each side with oil.
Coat food rack with cooking spray; place on grill over medium heat (300° to 350°). Place wedges on rack, and grill, covered with lid, 4 minutes on each side or until golden. Serve with salsa, if desired.