Wash the fennel and pat dry. Cut into very thin slices or slice on a mandolin.
Grate half the orange zest. Peel and finely dice the onion.
Squeeze 2 tbsp orange juice and 1 tbsp lemon juice.
Arrange the fennel, onion and salami slices on a plate or a board.
Mix the olive oil with orange juice, orange zest, lemon juice, honey and mustard. Season with salt and pepper. Pour the dressing over the fennel, stand for 10 minutes, then serve.