Heat small cast iron skillet over medium heat and add olive oil. Once the oil starts to sizzle, add cherry tomatoes.
Place tomatoes flat in the skillet. Leave tomatoes for 2-3 minutes on each side until tomatoes have some char marks, do not overcook. Turn heat off when both sides of tomatoes are blistered then set it aside.
Spread watercress evenly onto a large serving platter and add cherry tomatoes, pickled beets, and prosciutto slices on top of watercress. Sprinkle crumbled goat cheese over the salad.
In a ramekin, whisk together olive oil, apple cider vinegar, salt and pepper and drizzle over the salad. Serve chilled or at room temperature.