2 tablespoon extra-virgin olive oil, plus more for drizzling
1 onion, diced
1 stalk celery, sliced
1 carrot, peeled and diced
8 ounces Yukon Gold potatoes, scrubbed and cut into 1-inch pieces
Coarse salt and freshly ground pepper
1 bunch kale, stems removed, leaves torn into small pieces (4 cups)
1 (15-ounce) can navy beans, drained and rinsed
2 teaspoons red-wine vinegar