In a medium jar, combine olive oil, balsamic vinegar, minced garlic, Dijon mustard, and a pinch of salt and pepper. Shake vigorously for about 30 seconds until emulsified. Set aside.

Bring a large pot of salted water to a rolling boil. Add orzo and cook according to package instructions, typically 7-9 minutes until al dente. Drain and rinse under cold water.

Soak sun-dried tomatoes in hot water for about 5 minutes, then drain well.

In a large mixing bowl, combine spinach, cooled orzo, softened sun-dried tomatoes, and crumbled feta. Toss gently to mix.

Drizzle vinaigrette over the salad and toss gently until spinach wilts slightly.

Let the salad sit for about 15 minutes before serving for the best flavor.