In a large mixing bowl (or large serving bowl), combine the spinach, strawberries and walnuts.
To make the vinaigrette, combine the balsamic vinegar, olive oil, salt and pepper in a jar with a tight fitting lid. Give it a good shake for about 20 seconds.
When ready to serve, pour your desired amount of vinaigrette onto the salad, and crumble the goat cheese over the top. Use tongs to toss it all together, and serve!