The peppery taste of the watercress is offset by the sweetness of the oranges and creaminess of the cheese.
Using a sharp knife, cut off top and bottom of orange and slice away peel. Working over a medium bowl, cut out orange segments. Squeeze 2 teaspoons juice from membranes into a large bowl. Whisk in vinegar and oil; season with salt and pepper. Add watercress, orange segments, and almonds and toss to combine. Serve with cheese.
When buying watercress, look for bunches with bright, glossy green leaves that haven't begun to wilt. Store in a plastic bag, in paper towels, up to 5 days.