Whisk eggs, milk, salt, and pepper together in a bowl until well combined.

Melt butter in a skillet over medium heat and add red onion and corn, cooking for 2 minutes.

Pour the egg mixture into the skillet and gently scramble, stirring slowly until eggs are just set but still slightly soft.

Warm tortillas directly over a gas burner or in a dry skillet for 30 seconds per side.

Fill each tortilla with scrambled eggs and top with cheese, cherry tomatoes, avocado, and salsa.