In a medium saucepan, combine the rinsed quinoa and water (or vegetable broth). Bring to a boil over medium heat. Once boiling, reduce the heat to low, cover, and let it simmer for about 15 minutes or until the quinoa is fluffy and the liquid is absorbed. Remove from heat and let cool.
In a small bowl, whisk together the olive oil, balsamic vinegar, honey, salt, and pepper until well combined.
In a large mixing bowl, add the cooked quinoa, spinach, sliced strawberries, crumbled feta cheese, chopped walnuts, and red onion.
Drizzle the dressing over the salad and gently toss until everything is evenly coated.
Taste and adjust seasoning if necessary with additional salt and pepper before serving.