Heat olive oil in a frying pan. Stir in onion, garlic, chillies and eschalots. Stir fry until onion begins to soften. Stir in the beef mince, breaking it up and stirring with a spatula, until it is browned. Stir in the beans and the corn and about 1/2 cup of extra water. Continue to cook until the meat is cooked through and no longer pink.
Heat taco shells in the oven according to directions then stuff with the taco meat, cheese, lettuce and tomatoes.