Cook the jasmine rice according to package directions. While the rice simmers, prepare all other ingredients: cube the chicken, chop the vegetables, and dice the fruit. Pat the chicken cubes dry with a paper towel and season lightly with salt and pepper.
Heat the avocado oil in a large skillet or wok over medium-high heat. Once shimmering, add the chicken in a single layer, working in batches if necessary to avoid overcrowding. Cook for 2-3 minutes per side until golden brown and cooked through. Remove the chicken from the skillet and set aside on a plate.
Reduce the heat to medium. Add the chopped bell peppers and red onion to the same skillet and sauté for 4-5 minutes, until they begin to soften but remain crisp-tender.
Add the minced garlic and grated ginger to the pan. Stir constantly and cook for 30-60 seconds until fragrant.
Pour the soy sauce, rice vinegar, honey, and sesame oil into the skillet. Stir to combine, scraping up any browned bits from the bottom of the pan.
In a small bowl, whisk together the cornstarch and 2 tablespoons of cold water to create a smooth slurry. Pour the slurry into the skillet, stirring continuously. Bring the sauce to a simmer and cook for 1-2 minutes until it thickens into a glossy glaze.
Return the seared chicken to the skillet. Add the fresh pineapple and mango chunks. Gently fold everything together to coat in the sauce and let it simmer for 2-3 minutes for the fruit to warm through and the flavors to meld.
Serve immediately over the cooked jasmine rice. Garnish with fresh cilantro, sliced green onions, and sesame seeds, if desired.