Toast your walnuts, either in a pan on medium heat, or on a baking tray in the oven, for 5 minutes or until browning and smelling fragrant - mind not to burn! Make a vinaigrette - place mustard, salt, pepper & vinegar in a bowl & mix. Slowly add olive oil, whisking well as you go.
Peel and slice your oranges. Thinly slice your fennel. Separate your chicory leaves, and then your radicchio (slice some of these, and keep some whole). Assemble your salad in any which way you like. Drizzle your salad with the vinaigrette, and then sprinkle on your walnuts and dill.
This is a salad created to really let blood oranges shine, both visually and flavour wise.