Thinly slice the yellow pepper and red pepper, then fry them in a pan with olive oil and the chopped onion, until softened.
On a griddle, grill the chicken frankfurters.
Thinly slice the sweet green chilli pepper.
Cut the hot dog buns and warm them in the oven. Put the peppers, chicken frankfurters, slices of raw, green chilli pepper on the buns. Garnish with ketchup.