Prep your avocados: cut avocado down the middle and take out the pit. Scoop the flesh onto a cutting board and cut into chunks. This makes mashing easier.
Immediately place avocado in a mixing bowl and cover with the lime juice.
Mash until desired consistency is reached.
Stir in diced onion, tomatoes, garlic, cilantro, cayenne, and salt.
Adjust seasonings, if desired.
Cover tightly with saran wrap and chill until cold.