Make the beets: Preheat the oven to 400-degrees.
Stack 2 large sheets of heavy-duty aluminum foil on top of each other and fold in the sides to make a well.
Place the beets in the center of the well.
Drizzle the olive oil over the top and season with the salt.
Bunch up the ends, tightly sealing the foil around the beets.
Place the foil packet onto a quarter sheet pan and bake until a paring knife easily glides into the centers of the beets, for 50 to 70 minutes. Roasting time will depend on the size and freshness.
Once the beets are cool enough to handle, using paper towels, rub off the skins; refrigerate until cool, then slice into ¼-inch rounds.
Make the salad: Supreme two of the oranges, setting the segments aside. Squeeze the remaining juices into a liquid measuring cup.
Remove the peel and pith from the remaining orange and slice into ¼-inch rounds; set aside.
In the same measuring cup with the orange juice, add the vinegar, honey and whisk to combine,
While whisking constantly, drizzle in the olive oil to emulsify; season with salt and pepper, to taste.
On a large plate or platter, spoon half of the dressing across the bottom.
Place the beet rounds evenly over the bottom of the plate, layering if necessary.
Scatter the orange rounds and segments evenly over the beets.
Drizzle the remaining dressing evenly over the top.
Sprinkle the goat cheese and pistachios evenly over the top.
Top with a light sprinkling of flaky sea salt and mint leaves; serve immediately.