Fill a large bowl with 1 quart of warm water with the Kosher salt and sugar. Stir until the salt and sugar is mostly dissolved. Add the chicken and brine 15 minutes. Remove the chicken breast and rinse with cold water, then pat dry.
Soak the skewers in water a few minutes. Spear the shrimp, 7-8 per skewer. Season to taste with salt and pepper.
Preheat the oven to 450°F.
Preheat a large cast iron grill pan over high heat. Brush the chicken with the coconut oil. Seasoning both sides of the chicken with salt and pepper. Grill the chicken 1½ minutes per side. Transfer the chicken to a foil lined baking sheet. Pour on ¾ of the sauce.
Bake 8 to 10 minutes or until the chicken reaches 165°F. Remove from oven loosely cover with foil. Let stand 5 to 10 minutes.
Heat the grill pan, coated with nonstick cooking spray, on medium heat. Add the shrimp skewers and brush on half of the remaining sauce. Cook 2-3 minutes. Flip and brush on the remaining sauce. Cool 1-2 minutes. Transfer to a serving dish. Serve the chicken and shrimp along with rice and a veggie side dish.
Combine all of the sauce ingredients, except the diced mango, in a saucepan. Bring to a boil over medium heat. Simmer 5 minutes.
Mix the water and cornstarch. Add the diced mango to the pot. Simmer 4 minutes. Remove from heat.