Preheat the oven to 350 degrees F. In a small bowl, whisk together the brown sugar and hot water. Add the pistachios and toss until well coated. Pour mixture onto a large baking sheet that has been lined with a Silpat baking mat or parchment paper. Bake until pistachios are crisp, about 12-15 minutes. Remove from oven and let cool. Once cooled, break pistachios apart.
In a large bowl, add spinach, strawberries, avocado, goat cheese, and candied pistachios.
In a small bowl, whisk together olive oil, lemon juice, vinegar, and honey. Season with salt and pepper, to taste. Drizzle dressing over the salad. Serve immediately.
Note-I usually don't add the full 1 cup of pistachios to the salad, but I like to candy 1 cup at a time. I like to snack on them while I make the salad or save some for later. Add however many you like!