Whisk 3 tablespoons lime juice with 2 tablespoons water, 1 tablespoon sugar, 2 teaspoons fish sauce and 1 teaspoon sambal oelek in a bowl. Refrigerate until cold. Toss with 4 diced peeled kiwis, 1 cup bean sprouts, 1/4 small thinly sliced red onion and 1/2 cup torn fresh mint; season with salt. Pile 4 cups Little Gem lettuce on a plate. Top with the kiwi mixture.