2 tbsp. extra-virgin olive oil, plus more for drizzling
1 large yellow onion, chopped
8 oz. chorizo (approximately 2 1/2 links), sliced 1/4 inch thick
4 garlic cloves, finely chopped
1/4 tsp. red pepper flakes, or more to taste
8 cups water
1 lb. Yukon Gold potatoes, peeled and cut into 1-inch pieces
1 small green or savoy cabbage (1 lb.), cored and thinly sliced
1 (15-oz.) can navy or great northern beans
2 tbsp. kosher salt, or more to taste
freshly ground black pepper
juice of half a lemon