In a nonreactive mixing bowl (such as stainless steel or glass), combine the cucumber with the shallot and jalapeno pepper.
Combine the lime juice, vnegar, Splendar or sugar, and salt and pour over the salad. Stir. Add the cilantro and stir again. You can serve this right away, but 15 to 20 minutes of chilling time lets the flavors blend. Best eaten the same day though.