Bring a large saucepan of salted water to a boil. Have a large bowl of ice water nearby. Add the green beans, sugar snap peas, and asparagus to the pot and cook for 2 minutes. Drain, then immediately plunge the vegetables into the bowl of ice water to stop the cooking. When cool, drain and shake off as much excess water as possible.
Meanwhile in a large bowl, combine the olive oil, lemon juice, rice vinegar, Dijon mustard, honey, capers, dill and salt and pepper. Add the drained vegetables and the fennel and toss to coat well with the dressing. Serve at room temperature.