In a food processor, process all the ingredients for the pesto until smooth and creamy.
In a small saucepan, heat up apple cider vinegar, water along with salt and sugar for the pickling liquid until boiling and then pour the pickling liquid over sliced radish.
To make the sandwich, spread 1-2 tbsp pesto over simply soft sourdough bread and layer up with some sprouts, rockets, tomato, and avocado slices and pickled radish.