Bring a large pot of lightly salted water to a boil. Add pasta shells and cook for 8 to 10 minutes or until al dente. Rinse under cold water until cool.
In a large bowl, gently mix the cooled pasta, tuna, jalapeno chilli, onion and celery. In a separate bowl, mix the mayonnaise, sour cream, lemon zest, mustard and lemon juice. Stir the dressing mixture into the pasta salad to evenly coat. Season with salt and pepper and chill until ready to serve.