Place a cutting board on a rimmed baking sheet. Core the pineapple. Cut the pineapple, mango, and kiwi into bite-sized pieces and mix in a large bowl.
Pour any juice that has accumulated on the baking sheet into a small bowl; whisk in the lime juice and vanilla. Pour the juice over the fruit. Refrigerate at least 20 minutes.
Just before serving, slice the banana into the fruit salad.