Gather all of your ingredients.
Using a small paring knife, slice grape tomatoes in half. I prefer grape tomatoes as they have smaller seeds. Using a chef's knife, carefully chop the sliced tomatoes by rocking the knife back and forth. Strain the tomatoes to drain excess liquid.
Holding the avocado in your hand, with the pit facing the lower part of your palm, carefully use a chef's knife to slice the avocado in half lengthwise.
Twist the avocado to separate into two halves. Remove the pit by carefully hitting the end of the chef's knife against the pit itself and twist. The pit should easily pop out.
Using your paring knife, score lines in a hatch pattern by slicing vertically and then horizontally across the flesh, being mindful not to press through the skin.
Using a spoon, scoop out the avocado into a medium bowl.
Squeeze a half a lime over the avocado. The lime not only adds flavor, but also prevents the fruit from oxidizing and turning brown.
Using a fork, mash the avocado to your preferred texture (either smooth or chunky).
Mix in the chopped tomato and add the minced garlic. Season with salt and pepper to taste, starting with a half teaspoon of salt, a quarter teaspoon of pepper, and adjust accordingly.
Next, prepare the red onion. Rinse off your cutting board from the tomatoes and lay a piece of damp paper towel beneath the board. This will help secure the cutting board so that it does not move. Slice off the 'stem' end of the onion, and then slice the onion in half through the 'root' end. Peel away the outer paper layer.
Laying the flat end down against the cutting board, place a flat palm on the rounded part of the onion, and carefully slice horizontal slices ¾ of the way through (you should get about 3 slices). Rotate the onion and holding the outside, carefully slice vertical lines across the whole top, ¾ of the way through. The closer the slices, the finer the dice.
Rotate the onion again so that the root end is facing your palm, but the cut side is still facing down. Place your fingers on top of the onion but curl your fingers inward. This will protect your fingers from accidents! Carefully, run the center of the knife across the onion, slicing away from you, working from the outside in. Keep a single, straight motion all the way through for each slice, avoiding trying to 'saw' through the onion. This will significantly help against releasing too much of the amino acids that cause those tears!
13. Grab a handful of fresh cilantro. Roll the cilantro up as tightly as you can, and tucking your fingers in, gently glide the knife across the herbs, using your knuckles as a guide. Keep the tip of the knife resting on the cutting board as you chop in a forward motion. With one hand on the handle and the other safely on the top of the knife, rock back and forth until the cilantro is fully chopped.
Add the cilantro to the mixture and stir to combine. Taste to see if you need to add additional salt, pepper, or lime juice, and adjust as desired. While the guacamole should rest for a minimum of 30 minutes to allow all of the flavors to meld, an hour or more will yield a tastier dip. Cover and refrigerate.
Guacamole is best served the same day it's made, so plan accordingly! Serve alongside your favorite tortilla chips or favorite Mexican dishes.