In a food processor, pulse macadamia nuts until finely chopped. Remove all but 1/3 cup to a small plate. To processor, add lemon juice, cream cheese, cheddar cheese, garlic salt, black pepper, and cayenne. Pulse until smooth. Cover; refrigerate for 1 hour.
Shape 2 teaspoons cheese mixture into a ball; roll in chopped nuts. Repeat with rest of the cheese mixture. Top each with a slice of pimiento-stuffed green olive. Serve with crackers.