In a large bowl, combine the diced mangoes, cucumber, red bell pepper, red onion, and cilantro. Mix well to evenly distribute the ingredients.
In a separate small bowl, whisk together the lime juice, fish sauce, honey, and chili flakes if using. This dressing will bring all the flavors together.
Pour the dressing over the salad mixture and toss gently to combine everything evenly, being careful not to mash the mangoes.
Let the salad sit for about 10 minutes before serving to allow the flavors to meld beautifully together.
Serve chilled or at room temperature as a refreshing side dish or light meal option.