Before you start, bring a medium pot of salted water to the boil.
Cook rice in pot of boiling water for 20-25 minutes, until very tender. While rice is cooking, prep carrot. Drain rice and return to pot along with carrot. Season to taste with salt and pepper.
Prep onion. Heat oil in a large fry pan on medium-high heat. Cook onion for about 2 minutes, until soft. Add lemongrass paste, pork, chilli flakes and a pinch of salt and cook for about 5 minutes, stirring often, until brown and cooked through. Stir through soy sauce and season to taste with salt and pepper.
Prep cucumber and capsicum and toss in a small bowl with lime ponzu. Season to taste with salt and pepper.
To finish, prep lettuce, lime and coriander.
Serve lettuce cups filled with rice, pork and salsa. Top with sesame seeds, coriander and chilli flakes. Serve lime wedges on the side for squeezing.