Heat the vegetable oil in a large a pan over a medium-high heat and fry the pork mince with the red pepper for about five minutes or until the pork is cooked through and browned in places. Drain off any excess liquid and set aside.
In a large bowl, combine all of the remaining ingredients, apart from the lettuce leaves, then add the hot pork and stir to combine.
Taste the mixture and add more fish sauce or palm sugar, to taste.
To serve, arrange the lettuce leaves on a serving platter and spoon the pork mixture into the leaves.