Shrimp Salad with Cucumber and Fennel
2 pounds small shell-on shrimp
2 fennel bulbs, sliced crosswise ¼-inch thick, fronds reserved
1 English hothouse cucumber, sliced ¼-inch thick
1 small red onion, very thinly sliced into rings
1 tablespoon finely grated lemon zest
¼ cup (or more) fresh lemon juice
Coarsely ground black pepper
? cup olive oil
½ cup small dill sprigs
Cook shrimp in a large pot of simmering salted water until bright pink and cooked through, about 3 minutes. Drain and let cool.
Peel and de-vein shrimp and place in a large bowl. Add fennel, fennel fronds, cucumber, onion, and lemon juice and toss to combine; season with salt and pepper. Drizzle with oil and toss to coat. Add dill and lemon zest and toss again; season with salt, pepper, and more lemon juice, if desired. Top with more pepper just before serving.
Do Ahead: Salad can be made 4 hours ahead. Cover and chill.