In a large bowl, toss the purslane with the arugula, cilantro, parsley, and sprouts.
In a small bowl, whisk both oils with the vinegar, horseradish, and mustard until smooth.
Pour the dressing over the salad, season with salt and pepper, and toss to combine.
Crumble the goat cheese over the salad and sprinkle with walnuts and edible flowers, if using, before serving.