Halve the avocados and remove the pits, but set them aside. Remove from the skin with a big spoon and very coarsely chop avocado into big pieces. Place chopped avocado and minced jalapeno in a medium bowl.
Squeeze all the lemon juice over the mixture. Sprinkle liberally with garlic salt, adjusting to your taste, and stir, gently mashing some of the avocado pieces. Add chopped tomato at the end, stirring just until combined. Add 2 of the avocado pits back into the bowl (this really helps keep guacamole from turning brown). Serve chilled.
If desired, add extra cayenne or jalapenos for more kick. You can add more lemon juice if you like a little more tartness too.