On a platter arrange lettuce, leaving a 2-inch open rim at edge of platter. Combine bean dip and picante sauce. Spread bean mixture over lettuce, making a layer 1/4 inch thick. Next layer sour cream and avocado dip. Top with cheese, onions, and olives. Cover and chill 4 to 24 hours.
Before serving, sprinkle with chopped tomato. Arrange the chips or crackers on the platter around spread. Makes 16 appetizer servings.