Preheat the oven to 400 degrees.
Place the cumin, caraway, coriander, anise, and fennel in a small skillet and roast over medium heat until the seeds become fragrant. About 1 to 2 minutes. Remove from the stove and place in a coffee grinder or food processor and grind the seeds until they reach a powder-like substance.
Place the ground seeds and the sweet paprika, cayenne, red chili flakes, garlic, lime juice, 1/4 cup of olive oil, and salt into a small bowl and whisk together until well combined.
Rub about 1 tablespoon of Harissa on each Chicken breast (for a stronger flavor let sit for 2 hours or in the fridge overnight, but not necessary). Place on a rimmed baking sheet lined with parchment and roast for about 20 to 25 minutes or until chicken reached 160 degrees.
While the chicken is roasting place the frozen cauliflower rice in a medium saucepan and steam until soft. Add the fresh lime juice, cilantro, and 1 tablespoon of olive oil.
Layer each plate with the cilantro lime cauliflower rice and place a chicken breast on top. Decorate the rest of the plate with sliced avocado and grapefruit.