Fill a large bowl with ice water. Bring a large saucepan of salted water to a boil over high heat. Blanch the Brussels sprouts for 3 minutes. Transfer to the ice bath. Drain and pat the Brussels sprouts dry.
In a large bowl, beat the sherry vinegar with the flaxseeds, chia seeds, chlorella, wheatgrass powder, cumin, and ginger. Slowly whisk in the flaxseed oil until emulsified. Add the Brussels sprouts and onion, toss to combine, then season with sea salt and pepper, to taste.
Mound the mixed greens and arugula on a platter and top with the dressed Brussels sprouts, mint, and pistachios. Gently toss to coat. Garnish with the lemon zest. Enjoy.