Preheat oven to 425 degrees.

Drizzle the zucchini with a small amount of olive oil and toss to coat. Set aside.

Place the potatoes on a sheet pan. Drizzle with about 1 tablespoon of olive oil, season with a sprinkle of salt, and toss to coat. Bake for 15 minutes, then remove pan from oven. Add the zucchini to the pan, tossing to combine with the potatoes. Return to oven and bake for an additional 15 minutes.

Meanwhile, cook bacon in a skillet over high heat until crispy. Remove bacon to a paper towel to drain, and reserve the bacon drippings, adding enough olive oil to make ¼ cup.

In a small bowl, whisk together the chives, vinegar, and mustards. Slowly drizzle in the bacon drippings, whisking continuously. Season with a heavy pinch of salt and several grinds of black pepper.

Once the potatoes and zucchini finish roasting, remove from oven and place in a large bowl. Add the dressing and toss to coat. Add the corn, tomatoes, and 2 of the sliced scallions, and stir to combine. Reserve the last scallion for garnish when serving.

Serve warm or chill for several hours before serving to allow the flavors to meld.