Years ago a friend of mine shared a trick for making guacamole, simply place everything in a ziplock bag and bang it with a rolling pin or hand crush it. Give this method a try, it is so easy and mess-free.
Guacamole
2 avocados
2 tablespoons diced red onion
2 cloves garlic
1 plum tomato (optional)
cilantro
juice of 1 lime
salt
Cut two avocados in half, remove pits, and scoop flesh into the ziplock bag with a spoon. Peel the garlic and then crush into a paste using the side of a large knife. Add garlic, diced red onion, a tablespoon or so of minced cilantro, the juice of a lime, tomato (if using), and salt to taste. Press the air out of the bag and seal. Crush with your hands or bang with a rolling pin until smooth. Press all of the guacamole into one corner, cut the tip off the bag and pipe into a serving dish.