Preheat oven to 475°F.

Scrub beets and wrap in aluminum foil. Bake until tender and easily pierced with a knife, about 75 minutes or more, depending on their size.

Remove from oven and set aside to cool just enough to handle. The skins should slip off pretty easily—but if they don't, use a sharp knife or vegetable peeler to remove skin.

Slice beets into bite-sized cubes.

In a small bowl or a jar with a tight-fitting lid, combine the vinegar, harissa (or alternate mixture), cumin, coriander, salt, and pepper. Add olive oil and mix well.

Taste, and adjust seasonings if needed.

Toss beets, green onions, and red onion with dressing, to taste. (You might wind up with some dressing left over.)

Serve warm.