Preheat oven to 300 degrees F.
In a 2 quart baking dish (or 8x8 square pan), toss strawberries and balsamic vinegar. Bake strawberries for 50 minutes, checking every 15 minutes and gently tossing in the juices.
Meanwhile, cook quinoa if needed.
Then, heat a heavy skillet (cast iron if you have it) over medium high heat. Season fillets with pepper and salt. When skillet is hot, add vegetable oil, then cook fillets to medium doneness, about 3 minutes per side. Remove from pan and set aside on a cutting board to rest. After about 5 minutes (more time is OK), thinly slice steak against the grain.
Reduce the skillet heat to medium and add green beans. Add 2 tablespoons of water and cook till evaporated or green beans are crisp tender, about 4 minutes. Remove skillet from heat.
When strawberries are done baking, assemble salad. Layer a large platter with the spring mix greens, then spoon cooked quinoa on top. Drizzle with extra virgin olive oil, about 1 tablespoon. Layer green beans on top of quinoa. Place steak slices on top of salad then spoon cooked strawberries and juice on top. Lastly, arrange sesame seeds, mozzarella pearls, and basil all around salad to your preference. If desired, sprinkle a small amount of fresh, ground black pepper on top.