Toss the shallots and vinegar in a medium bowl; set aside. Prepare a medium grill fire. Put the eggplant in a bowl and sprinkle with 2 Tbs. of the oil, the cumin, coriander, salt, and pepper; toss to coat. Grill until well browned and softened, 3 to 5 minute per side. When cool, cut into 1/2-inch dice. Toss in the bowl with the shallots; add the herbs. Transfer to a serving bowl. Just before serving, drizzle with the remaining 2 Tbs. oil and season with salt.