- Combine riced cauliflower and water; cover with vented plastic wrap and microwave on High 6 minutes.
- Meanwhile, brush chicken with olive oil; season all over with 1/2 teaspoon each salt and pepper. Grill on medium 5 minutes, turning over once halfway through. Whisk together sweetened cream of coconut and hot sauce; brush onto chicken. Grill until cooked through (165°F), about 5 minutes longer, brushing and turning 2 more times. Grill 2 limes, halved, until lightly charred, 2 to 3 minutes.
- Toss cooked cauliflower with black beans and 1/4 teaspoon salt. Serve chicken over cauliflower with limes, garnished with chopped cilantro.