Slice the Sweet Onion (1) into quarter-inch rounds and place on a baking sheet. Shuck the Corn (1 ear) and place it on the sheet. Brush the onions and corn with Olive Oil (1 tablespoon), just so it's lightly coated.
Place the corn and sliced large sweet onion on the grill and cook, turning every so often to avoid burning until the corn and onions are tender and have taken on a little char. Transfer the vegetables to a sheet pan and set aside.
Using a vegetable peeler or a mandoline, set on very thin slices to slice the Zucchini (1) into thin ribbons and transfer to a large bowl.
Cut the Campari Tomato (4) into bite sized wedges and add to the zucchini. Separate the onions into rings and add them to the salad. Cut the corn off the cob and transfer to the salad. Add the Queso Fresco (3/4 cup) toss into the salad.
Just before serving, toss the salad with the dressing. To make the dressing, combine Olive Oil (3 tablespoon), Lime (2 teaspoon), Lime Juice (1 tablespoon), Dijon Mustard (1 teaspoon), Ground Black Pepper (1/4 teaspoon) and Kosher Salt (1/2 teaspoon) and sprinkle with the Fresh Cilantro (1/2 cup).