1) Mince onions and rinse them well under cold water to mellow them a bit.
2) Scoop out avocados and add to a bowl with other veggies. Mash together well.
3) Peel grapefruit. Use a paring knife to cut out each grapefruit segment, removing the fruit from the pith parts.
4) Add grapefruit segments to guacamole, breaking up the segments a bit as you add them.
5) Season guacamole with salt and serve with chips!