Store any leftover tuna pasta salad in an airtight container in the refrigerator for up to two days. Rinse the cooked pasta under cold water to stop overcooking. Use high-quality tuna for better flavor. Try using an English cucumber for less seediness and no peeling. Mix in hard-boiled eggs or diced celery for added textures and flavors. Taste as you go to adjust the flavors before serving.