1. Place spinach and strawberries in a large mixing bowl.
2. In a liquid measuring cup (or small bowl), whisk together the olive oil, balsamic vinegar, maple syrup, and Dijon mustard. Season to taste with salt and pepper. Sometimes I place all of the ingredients into a mason jar, seal with a reusable lid, and give it a good shake to mix.
3. Drizzle about 2 tablespoons of the vinaigrette over the spinach and strawberries. Gently toss to coat. Add more dressing as needed until the spinach leaves are just lightly coated with dressing. Transfer the dressed spinach and strawberries to a serving bowl or platter.
4. Top the dressed salad with pecan pieces, optional feta cheese, and green onion tops (green parts only). Sometimes I serve these on the side, so everyone can add or omit ingredients based on their preferences or dietary needs. 
5. Serve cold with remaining vinaigrette either drizzled on top or served on the side (about 1 tablespoon vinaigrette per serving)

Storage: This salad is best served right after preparing. However, you can store the salad ingredients and prepared vinaigrette separately in the refrigerator for up to 3 days. Assemble salad just before serving.