Cook potatoes in boiling water to cover 25 to 30 minutes or until tender; drain and cool. Cut into thin wedges.
Sauté bacon in a large skillet over medium-high heat 2 minutes. Add green onions, and sauté 2 minutes. Stir in flour, and cook, stirring constantly, 1 minute. Gradually stir in 2/3 cup water and vinegar, and cook, stirring constantly, until thickened. Stir in salt and pepper. Toss with potato and pimiento. Serve warm.