Preheat the oven to 400 degrees F.
In a food processor, pulse the cauliflower in batches until the florets turn into coarse crumbs. Be careful not to overstuff the bowl - you don't want it to turn to mush. You should have 4 cups of cauli rice. Set aside.
In a large oven-proof skillet heat 1 tablespoon of olive oil over a high flame. Season the chicken with salt and brown on all sides until nicely golden, about 7 minutes total. Remove to a bowl and toss with 1 tablespoon of the harissa.
Add the onions and 1 tablespoon olive oil to the pan and sauté until translucent, 5 minutes. Stir in the garlic, cumin, ginger and remaining 1 tablespoon harissa. Cook for 1 minute, then fold in the asparagus, cauli rice, dates, lemon juice and 1 teaspoon salt. Spread the cauli mixture in an even layer and nestle the chicken on top. Transfer the pan to the oven and roast for 20 minutes, until the cauli couscous is soft and the chicken is tender.
Garnish with the pistachios and serve right in the pan!