1. Combine wasabi, lemon and lime juices, and 2 teaspoons water in a small bowl. Let stand for 15 minutes.

2. Meanwhile, break egg into food processor before turning it on. Slowly add oil, a few drops at a time at first, then in a thin steady stream until mixture is thick, 2 to 3 minutes. Add wasabi mixture, soy sauce, and coriander, and pulse to combine, about 5 seconds. Refrigerate until ready to serve.