Scrub potato; cut into 6 wedges. Soak potato wedges in ice water for 30 minutes; drain and pat dry with paper towels.
Coat an 8-inch square pan with cooking spray. Arrange potato wedges in one layer in pan; brush with margarine. Combine oregano and next 3 ingredients; sprinkle mixture evenly over potato wedges. Bake at 350° for 30 minutes, turning twice. Remove from oven; sprinkle with cheese, and serve immediately.