Place golden beets in a shallow baking dish. Stir water and 2 tablespoons olive oil together in a small bowl and pour over beets, tossing them in the liquid to coat completely. Cover the baking dish with aluminum foil.
Bake in the preheated oven until beets are tender when pierced with a skewer, 45 to 55 minutes. Remove form oven, uncover, and let cool for 10 minutes. Slip skins off beets and cut them crosswise into thin 1/4-inch slices.
Whisk 3 tablespoons olive oil and balsamic vinegar together in a small bowl. Add orange juice, honey, orange zest, cayenne pepper, salt, and black pepper and whisk until vinaigrette is well combined.
Spread beets onto a plate and drizzle with vinaigrette. Toss gently with sliced red onion and season with parsley.