Place a saucepan over high heat and add the oil, onion, and salt. Saute for 5 minutes until the onion is translucent.
Add the ground beef and saute until browned.
Mix in the remaining ingredients (except the buns and cheddar).
Reduce the heat to medium and simmer for 30-40 minutes, or until the mixture is thick and saucy.
Serve on a burger bun, topped with cheddar cheese and mayonnaise.