Halve avocados and carefully remove the pits. Add the pits to a medium mixing bowl (the pits will keep the avocados from oxidizing). Using a sharp knife, slice the avocado flesh (still in the skin) diagonally into ¼-inch slices, then slice again in the opposite direction to create cubes. Repeat for the remaining avocado halves. Use a spoon to scoop out the flesh and add flesh to the mixing bowl.
Add the lime juice, crushed garlic, salt, and ground coriander, and mix well. You want some of the avocado to mash up as you mix, but retain some of the cubes for a hybrid smooth/chunky guacamole. Serve immediately.