Preheat your oven to 425°F and line a baking sheet with parchment paper.
Pat the skirt steak dry with a paper towel to ensure a good sear, then rub with 1 tablespoon of olive oil.
Season both sides of the steak evenly with sea salt, black pepper, and garlic powder.
Place the steak on the prepared baking sheet and roast for 8 to 10 minutes for medium-rare, or until it reaches your desired doneness.
While the steak is roasting, halve the cherry tomatoes and thinly slice the red onion.
In a small bowl, whisk together the remaining 0.5 tablespoon of olive oil, red wine vinegar, and dried oregano to create the dressing.
Toss the tomatoes and onions with the dressing in a medium bowl and let the flavors meld while the steak finishes.
Once the steak is done, remove it from the oven and let it rest on a cutting board for at least 5 to 7 minutes.
Slice the steak thinly against the grain and serve immediately alongside the fresh tomato and onion salad, garnished with chopped fresh parsley.