To make the vinaigrette, add a pinch of salt and the sherry vinegar to the shallots in a small bowl. Let steep for about 10 minutes. Whisk in maple syrup and walnut oil. Season to taste with salt and pepper.
Wash and spin dry the greens.
Core and cut persimmons into ½-inch-thick wedges and transfer to a low, wide salad bowl.
Slice fennel.
Salt persimmons and fennel lightly, then dress with vinaigrette. Add salad greens, whatever you’re using, and gently toss with dressed persimmons to coat leaves. Make sure the persimmons and fennel are well distributed and prominent.
Scatter over the pomegranate seeds along with any collected juices and a few nice fennel fronds (if you saved any). Garnish with the nuts and serve. Candied walnuts or pecans, bought or home-made, work very nicely as well.