Ham salad with watercress and potatoes

Sarah liked this and was heartbroken that she forgot to bring the leftovers back to Stockton, so we made it again the next weekend.

Two bunches of watercress, washed and dried
1 lb small red potatoes, washed and cut in quarters
1/2 lb leftover ham, cut into 1/3" cubes

Boil the potatoes until just tender, fry or bake the cubed ham to reheat. Toss the watercress, potatoes, and ham with the dressing below and serve warm. Grind pepper on individual servings at the table to taste.

Dressing:
2 tbs white wine vinegar
1 tbs balsamic vinegar
1 tbs grainy mustard (not seeds, from a jar)
Salt
2 tbs EVOO
Mix all the dressing ingredients except the oil first, then drizzle the oil in while beating the dressing to emulsify; (do this just before tossing the dressing into the other ingredients).

Note: what we get in CA seems to be "upland cress" which is paler and more delicate than watercress, but it has a similar flavor.