In a medium bowl, stir the red-wine vinegar with 1-1/2 tsp. salt until it has dissolved. Add the onion. If the vinegar doesn't cover the onion, add water to cover. Let sit for 15 minutes. Meanwhile, in a small bowl, whisk the chives, olive oil, and balsamic vinegar. Season to taste with salt and pepper.
Core and cut the tomatoes in half lengthwise and then cut each half lengthwise into 1/4-inch-thick slices. Put the tomatoes in a wide serving bowl. Pour the vinaigrette over the tomatoes and marinate them for 15 minutes.
Drain the onions, pressing them lightly to squeeze out any extra vinegar. Rinse the onions quickly and then lightly squeeze again. Add the onions to the tomatoes and toss. Season to taste with salt and pepper, top with the Gorgonzola, and serve.
This tomato salad is delightful with grilled rib-eye or flank steak marinated in olive oil, lemon juice, garlic, and rosemary or oregano.
nutrition information (per serving):
Photo: Scott Phillips