In a small bowl whisk together the lime juice with the olive oil, maple syrup, chili powder and sea salt. Taste and adjust seasonings with more of the above until your taste buds are happy. Set aside until needed.
Assemble the Salad:
Just before serving, peel and dice both the mango and avocado into 1 inch cubes. Discard the pits.
Transfer to a salad bowl together with the red onion and drizzle with the lime vinaigrette over the top. Use two flat spatulas to gently toss everything to coat without mashing the avocado. Sprinkle with the fresh cilantro leaves and serve promptly.