Toast the hazelnuts in a dry 24 cm / 10-inch skillet over medium heat for 4 to 5 minutes, shaking the pan often, until they smell toasty and the edges turn golden. Tip them onto a plate right away, because they keep darkening in the hot pan and burnt hazelnuts taste bitter. Cool for 5 minutes, rub off the loose skins in a clean towel, then chop roughly.

Slice the top and bottom off 2 oranges, then cut away the peel and white pith, following the curve of the fruit. Cut between the membranes over a bowl to release the segments, then squeeze the membranes over the same bowl. Juice the third orange and measure 60 ml / 1/4 cup. In the jar, shake that juice with the olive oil, vinegar, Dijon, honey, salt and pepper.

Quarter the radicchio, cut out the core, and slice the leaves into 1 cm ribbons. Submerge them in a large bowl of ice water. Shave the fennel as thin as you can and slice the onion. Toss both with half the dressing in the 3-quart / 2.8 L salad bowl, then leave everything to sit for 10 minutes.

Drain the radicchio and dry it in a salad spinner or between clean towels. Add it to the fennel bowl along with the beans, orange segments and remaining dressing. Toss gently, then divide among 4 bowls. Top with the goat cheese, hazelnuts and fennel fronds, and serve within 20 minutes.