Gently simmer poaching water and salt in a saucepan. Add tenders; poach partly covered 8 to 12 minutes until thickest centers reach 165°F.
Drain; cut into small pieces and spread in a shallow container. Promptly refrigerate about 60 minutes until 40°F or colder, included in prep time.
Warm oil in a small skillet over low. Stir curry powder 30 seconds until fragrant; transfer to a bowl and cool 5 minutes.
Whisk yogurt, mayonnaise, and lime juice into cold curry oil. Fold in cold chicken, apricots, and cashews.
Divide arugula among 4 bread slices; top each with one-quarter salad. Close with remaining bread; halve.
Serve cold or refrigerate at 40°F or below; transport with ice packs.