Preheat your oven to 400°F and line a baking sheet with parchment paper.
Toss the cubed red beets with 1 teaspoon of olive oil and a pinch of sea salt on the prepared sheet.
Roast the beets for 25 to 30 minutes until they are tender and slightly caramelized.
Season the strip loin steak evenly on both sides with the remaining sea salt, black pepper, and fresh thyme.
Heat the remaining 1 teaspoon of olive oil in a cast-iron skillet over medium-high heat until shimmering.
Place the steak in the hot skillet and sear for 4 to 5 minutes per side for medium-rare doneness.
Transfer the steak to a cutting board and let it rest for at least 5 minutes to keep it juicy.
In a large bowl, whisk together the balsamic vinegar with any juices released from the resting steak.
Add the baby arugula and roasted beets to the bowl, tossing gently to coat them in the dressing.
Slice the strip loin against the grain and serve the warm steak strips over the beet and arugula salad.