Bring potatoes and water to cover to a boil in a Dutch oven over medium-high heat. Cook 15 to 20 minutes or just until tender; drain well. Cool 15 minutes, and slice into wedges.
Whisk together mayonnaise and next 5 ingredients in a large bowl. Add potatoes, green onions, and 3 Tbsp. crumbled bacon; gently toss to coat. Season with salt to taste. Sprinkle with remaining bacon. Garnish, if desired.