Separately blanch and shock the haricots verts, pearl onions, and cauliflower. Boil beets until fork tender. Layer the vegetables in a 1-quart pickling jar. Bring pickling liquid to a boil and reserve 1/2 cup for vinaigrette, pouring the rest over the blanched vegetables. Let sit overnight or at least 4 hours. Make vinaigrette with 1/2 cup pickling liquid and olive oil. Toss with greens. Arrange vegetables and crumble with goat cheese.