Place the burger patties on the grates of the grill. Grill for about 20 - 25 minutes, depending on the thickness of the burger. The LESS LOOKING the more COOKING. So if you check on your burgers less, they will be finished faster.
In the meantime, slice the avocado.
In the last couple minutes, throw on the pineapple slices to give them some grill marks and toast your bun.
To assemble: spread mayo on the bottom bun, place your burger, pineapple, avocado, and cilantro and top with the bun. Serve immediately. Enjoy!