Rinse and remove core from the Napa cabbage, then chop. Rinse and quarter the pears, remove seeds and cut into cubes, then toss with the lemon juice. Cut the ham into small cubes. Rinse the chives, skake dry, then finely slice.
Combine the oil with the vinegar and season with salt, pepper and a pinch of sugar. Toss the Napa cabbage with the pears, chopped ham, and the vinaigrette. Arrange into shallow bowls and garnish with chopped chives. Serve immediately.