Bring poaching water and salt to a gentle simmer in a saucepan. Add chicken tenders, cover partly and poach for 8 to 12 minutes until the thickest centers reach 165°F.
Drain chicken, cut into small pieces and spread in a shallow container. Refrigerate promptly for about 60 minutes until 40°F or colder; prep time includes chilling.
Warm oil in a small skillet over low heat. Stir in curry powder for 30 seconds until fragrant, then transfer to a bowl and cool for 5 minutes.
Whisk yogurt, mayonnaise and lime juice into the cooled curry oil. Fold in cold chicken, diced apricots and chopped cashews.
Divide arugula among 4 bread slices and spread one-quarter of the salad over each. Close with remaining bread and cut in half.
Serve cold or refrigerate at 40°F or below, packing with ice packs for transport.