Beet-and-potato salad

Using some of the beautiful baby beets my mom brought me from her garden, and a few gold fingerling potatoes, I made a really nice potato salad.

4 medium gold potatoes, cut into pieces and boiled
4 medium beets, roasted and peeled and cut into pieces
3 tablespoons red wine vinegar
3/4 cup chopped onion (optional)
1 tablespoon capers
1/2 cup mayo
salt
cayenne pepper
1/4 cup peas (optional)

Combine the beets and 2 tablespoons red wine vinegar, and let sit for 30 minutes. Drain. Combine with the rest, mix until well blended, and adjust seasonings to taste.