If using wooden skewers, soak them in warm water for at least 30 minutes before beginning to prevent them from burning on the grill.
In a medium bowl, whisk together the pineapple juice, soy sauce, lime juice, garlic, and ginger. Cut the tofu into 1-inch cubes and add them to the sauce, making sure all the pieces are submerged. Marinate for at least 15 minutes.
Remove the tofu and transfer the leftover teriyaki marinade to a small saucepan. Whisk in the arrowroot and set over medium heat. Simmer gently for about 5 minutes until the sauce thickens, then set aside and let cool.
Seed and slice the pepper, cut the onion into large chunks, and peel, pit, and cube the mango, making the pieces all as even as possible. Thread the marinated tofu, vegetables, and fruit onto your skewers in an alternating pattern.
Heat the grill to medium-high. Place the skewers on the hot grill, brush with the thickened teriyaki sauce, and let cook for 4 – 6 minutes. Once browned on the bottom, flip the skewers and repeat.
Transfer the skewers to a plate and top with fresh cilantro. Serve additional teriyaki sauce on the side for dipping, if desired.