Place the garlic, ginger, lemongrass in a food processor and blitz until finely chopped. Alternatively, you can use a mortar and pestle to pound the garlic, ginger, and lemongrass into a paste.
Heat oil in a frying pan or wok over medium-high heat, then add in the pork. Occasionally stir the pork and cook until most of it becomes crispy, this could take around 5 minutes.
Push the pork to one side of the pan, and if it's too dry, add another tablespoon of oil to the other side. Add in the chopped garlic, ginger and lemongrass. Stir fry for 1 to 2 minutes, or until it becomes fragrant, making sure not to let it burn.
Add in the chillies, soy sauce, fish sauce, and sugar, then stir-fry until the sugar dissolves. The pork should look darker and caramelised, this may take about 2 to 3 minutes. Have a taste and add salt or pepper to your liking if needed.
Remove the pan from the heat, then add in the lime juice, tomatoes, onion, coriander and mint. Give it a good toss to combine. Have a taste and add more lime juice to your liking if needed.
To serve the Asian Lettuce Wraps, let your guests serve themselves by placing the pork stir-fry in a bowl with a serving spoon. Arrange the lettuce beside the bowl and add small bowls of sliced chillies, chopped peanuts, and lime wedges. Best served warm or at room temperature, but doesn't reheat well.