Step 1
In a food processor, process the oil, soy sauce, chopped spring onions, chilli, if using, ginger, garlic, lime zest, sugar, thyme, allspice, cinnamon, 1/2 tsp sea salt flakes and 1/2 tsp freshly ground black pepper until well combined. Reserve 1/4 cup (60ml) of jerk mixture. Transfer the remaining jerk mixture to a large bowl with the chicken and turn to coat. Cover and place in the fridge for 6 hours to develop the flavours.
Step 2
To make the coconut rice, drain the beans, reserving the liquid in a large measuring jug. Add enough coconut milk to the jug to measure 2 1/2 cups (625ml) liquid in total (top up with water if necessary). In a large heavy-based saucepan, combine the coconut milk mixture, beans, oil, sugar, thyme, chilli, if using, and 1 1/4 tsp sea salt flakes. Bring to the boil over medium heat. Add the rice and stir to combine. Reduce to a simmer. Cook, stirring occasionally, for 5-6 mins or until liquid evaporates to just below the surface of rice. Reduce heat to low. Cover and cook for 20 mins or until the rice is almost tender and liquid is absorbed. Remove from heat and set aside, covered, for 15 mins or until the rice is tender. Use a fork to separate the rice and beans, discarding the thyme and chilli.
Step 3
In a large bowl, toss the mango and pineapple with lime juice and 1/2 tsp of the reserved jerk mixture. Season with sea salt flakes. Set aside, tossing occasionally, for 10 mins to soak. Transfer relish to a serving bowl.
Step 4
Prepare a charcoal barbecue for medium-high heat. Transfer the chicken to a plate and pat dry with paper towel. Barbecue chicken, turning as needed and basting with the remaining reserved jerk mixture, for 6-8 mins each side or until the chicken is browned all over and cooked through. Transfer to a carving board for 10 mins to rest. Thickly slice.
Step 5
Coat the extra spring onions with the extra oil. Barbecue, turning as needed, for 4 mins or until lightly charred. Season and transfer to a serving platter with the relish. Top with the chicken.
Step 6
Cut the zested limes in half. Serve the chicken with the lime and coconut rice.
Serve with thyme sprigs.