1. Layer all the cheese and meat on cutting surface and cut into long thin slices and then cut across to obtain small squares of meat and cheese.
2. Put in bowl and add onion, oregano and mayonnaise and peppers if using hot peppers.
3. Cover and chill until ready to serve.
4. When ready to serve add tomatoes and shredded lettuce,mixing well.
5. Serve with slices of bread rounds or crackers.