Ingredients

• 2 seedless cucumbers (1 1/2 to 1 3/4 pounds total)
• 1 tablespoon sugar
• 1/4 cup distilled white vinegar
• 2 teaspoons grainy mustard
• Bibb or Boston lettuce leaves
• 2 tablespoons mild extra-virgin olive oil
• Equipment: an adjustable-blade slicer

Instructions

1. Cut cucumbers into thin (1/16-inch) rounds with slicer. Toss with 2 teaspoons salt in a colander, then drain 30 minutes. Squeeze excess liquid from cucumbers.
2. Whisk together sugar, vinegar, and mustard in a large bowl, then stir in cucumbers. Marinate, chilled, at least 2 hours.
3. Drain cucumbers, reserving marinade, and mound on lettuce. Whisk oil into reserved marinade and drizzle over salad.