Slice your cucumbers thinly on an angle so they curl slightly and hold the dressing well. Do the same with the fennel, keeping the slices fine so the flavor doesn't overwhelm the dish. I like to sit both in a bowl of cold water for a few minutes, since it keeps them extra crisp before mixing.
Wash your cherries, then halve and pit them over a bowl to catch any juice. Pick the fennel fronds and any fresh herbs you're using, and set them aside. Having everything prepped before you start mixing makes the assembly much faster and less messy.
Add your pine nuts to a dry frying pan over low to medium heat, or pop them in a low oven for a few minutes. Watch them closely since they can go from golden to burnt in seconds. Once they smell nutty and look lightly browned, take them off the heat immediately.
In a large mixing bowl, add the sliced cucumber, drained fennel, half of the cherries, and the watercress or rocket. Toss everything gently so the leaves don't bruise or wilt too quickly. This forms the crisp, fresh base that the rest of the salad builds on.
Whisk together the balsamic vinegar, honey, a good glug of olive oil, salt and pepper until it looks glossy and combined. Pour this over your salad base and toss again so everything is lightly coated. Taste as you go, since you can always add a touch more honey or vinegar to balance it.
Spoon the dressed salad into your serving bowl and scatter the crumbled goat's cheese and remaining cherries on top. Finish with the toasted pine nuts for crunch and a scattering of fennel fronds for color. Serve right away while the cucumber is still cold and crisp.