Wash fennel. Trim off feathery leaves. If desired, chop enough of the leaves to make 2 tablespoons; set aside. Trim fennel bulb. Chop enough of the bulb to make 1 cup. Cut remaining bulb into strips to use for dippers.
In a medium bowl combine chopped fennel, onion dip, red onion, and green onion. Serve immediately or cover and chill up to 24 hours. (Wrap and chill fennel leaves, if using.) To serve, spoon dip into serving bowl and sprinkle top with fennel leaves, snipped lemon thyme, and snipped chives.
Serve with vegetable dippers. Makes about 2-1/4 cups dip.