Toast the bread. In a bowl, mash the avocado with a fork until smooth. Mix in the cilantro and lemon juice to taste, and season with salt and pepper to taste. Spread the avocado onto the bread slices.
Preheat a non-stick pan over medium-low heat. Once hot, add the oil to the pan. Crack eggs on a flat surface and into the pan, being careful not to break the yolk. Cook until the whites of the eggs are firm and no longer runny.
Melt the butter in a nonstick pan over medium heat. Fry the ham until golden brown.
Serve the avocado toast with eggs, ham, and orange juice.