Roasting beets accentuates their natural sweetness, while toasted pumpkin seeds and arugula bring forth contrasts in texture and flavor, respectively. Radishes are thrown in for good measure. I used candy-striped beets here, but you should buy whatever looks best.
Preheat the oven to 375 degrees.
In a bowl, toss the beets in enough olive oil to coat. Season with salt and pepper, to taste. Wrap the beets individually in aluminum foil and place onto a baking sheet. Roast the beets for 30 minutes, or until a paring knife inserted into the center goes through easily. In the last 15 minutes of roasting, spread the pumpkin seeds onto another baking sheet and place in the oven.
Meanwhile, add the red wine vinegar to a bowl, and whisk in the olive oil. Season the dressing with salt and pepper, to taste. Add the oregano.
When the beets and pumpkin seeds are done, remove them from the oven and let cool. Once the beets have cooled, remove them from their foil packets, peel them, and cut into approximately ¼-inch-thick rounds. Toss them together by hand with the radishes and arugula in the dressing. Serve.