In a medium bowl whisk together lime juice, 1 tablespoon chopped mint, honey (or pineapple juice for Whole30), and a pinch of salt to make the marinade.
Place chicken breasts in a covered dish or container and pour the marinade over them. Cover and refrigerate for at least 2 hours or overnight.
Preheat the grill to medium-high and place a grill basket on the grates.
Toss cauliflower florets with melted coconut oil to coat, then place them in the grill basket. Grill, stirring occasionally, until tender and charred, about 10–15 minutes.
While the cauliflower cooks, grill the marinated chicken over indirect heat until cooked through, about 6 minutes per side; remove and let rest covered.
Increase grill heat to high and char the sliced onion rings and pineapple rings about 1–2 minutes per side until nicely browned; set aside.
Place the cooked cauliflower, chopped cilantro, 1 tablespoon mint, and a pinch of salt in a small food processor and pulse until it reaches a rice-like texture.
Transfer the cauliflower 'rice' to a bowl and stir in 2 tablespoons pineapple juice and the toasted coconut flakes.
Divide the cauliflower rice between two bowls and top each with a grilled chicken breast, sliced avocado, grilled onion and pineapple, and sprinkle with roasted macadamia nuts.