In a large bowl, combine the mangoes, carrots, red bell pepper, cucumber, cilantro, and green onions. Toss gently to mix the ingredients.
In a separate small bowl, whisk together the lime juice, fish sauce, honey, sesame oil, minced garlic, and red pepper flakes until well combined.
Pour the dressing over the salad and toss gently to coat all the ingredients evenly.
Let the salad sit for about 10 minutes to allow the flavors to meld.
Just before serving, sprinkle the chopped roasted peanuts on top for added crunch.