Preheat oven to 450°F. In a single layer on a large baking sheet, toss diced rhubarb stalks with organic evaporated cane juice.
On a separate large baking sheet, toss fennel bulbs with 1 tbsp extra-virgin olive oil and sea salt and fresh ground black pepper.
Roast rhubarb until tender, about 7 minutes. Roast fennel until tender, about 20 to 25 minutes.
Set aside both sheets to cool slightly. In a large skillet on medium, toast chopped unsalted pistachios, stirring occasionally, until fragrant, about 3 minutes. Set aside.
In a large bowl, whisk balsamic vinegar, 1 tbsp extra-virgin olive oil and salt and pepper, to taste. Add baby spinach, chives, roasted rhubarb and fennel; toss to coat with dressing. Garnish with crumbled goat cheese and toasted pistachios.
This salad is a perfect take-to-go meal this time of year. Top off your bento box salad with a side of nuts, seeds, fermented pickles or fresh fruit. If you can't find kabocha in your area, try using butternut squash (halved and peeled) instead.