In the bottom of a 7‑quart slow cooker, whisk together 1 1/3 cups full‑fat coconut milk, 1 1/3 cups mango juice, 2 teaspoons minced fresh ginger, 2 tablespoons green curry paste, and a pinch of sea salt until smooth. Stir in the sliced carrots.
Add the 1 pound boneless, skinless chicken breasts or thighs to the sauce, spooning sauce over the top to coat. Cover and cook on LOW for 5–6 hours, until the chicken is tender and cooked through.
Remove the cooked chicken from the slow cooker, place on a plate, and cover to keep warm. Leave the sauce in the slow cooker.
In a small bowl, remove about 8 teaspoons of sauce from the slow cooker and whisk the 4 teaspoons tapioca starch into that sauce until completely smooth and lump‑free.
Whisk the starch mixture back into the slow cooker. Add the 2 cups broccoli florets and the cubed 2 red bell peppers, stir to combine.
Cover the slow cooker, set it to HIGH, and cook 1–1.5 hours more, until the sauce has thickened and the broccoli and peppers are tender.
While the sauce is cooking, make the cauliflower rice: place the 6 cups cauliflower florets in a food processor and pulse until broken down to a rice‑like texture. Transfer the cauliflower rice to a large skillet.
Heat the 4 teaspoons coconut oil in the skillet over medium‑high heat. Add the cauliflower rice and the 4 tablespoons unsweetened coconut flakes. Cook, stirring occasionally, until the cauliflower is lightly golden, about 2–3 minutes. Cover, reduce heat to medium, and cook until the cauliflower is tender, about 2–4 minutes more. Remove from heat and set aside.
When the sauce has thickened, shred the reserved chicken with two forks and stir the shredded chicken back into the slow cooker to heat through.
Divide the cauliflower rice evenly among 4 bowls. Top each bowl with the chicken curry and the cubed mango.
Garnish with sliced green onion and cilantro, then serve.