Starting with the mango, remove the skin and cut the mango into bite sized pieces (making sure to avoid the tough core in the center). Add to a bowl.
Cut the avocadoes in half, remove the pits, and scoop them out of the skin carefully. Cut into bite sized pieces and add to the bowl.
Finely dice the jalapeno and red onion. Roughly chop the cilantro. Add to the bowl.
Dress the cut up salsa with the olive oil, lemon juice, salt, and pepper. Mix gently so as to ensure you aren't breaking up the avocado. Enjoy!