Put the metal blade chopping in your food procesor, then place the onion, lemon juice, mayonnaise, chili peppers and salt in the work bowl. Run the processor nonstop for 10 seconds. The onion should be minced, and the other ingredients blended together. Use a tablespoon to scoop out large chunks of avocado into the work bowl. Clean out each avocado shell as thoroughly as possible. Distribute the chunks of avocado around the chopping blade of the food processor. Pulse process two or three times, until the mixture is churned, but lumpy (like cottage cheese).