Rinse the lentils under cold water. Place in medium saucepan with 3 cups of water and bring to a boil. Reduce heat to low and simmer for about 15 minutes, or until tender. Drain any excess water.
In a small bowl, mix together lime zest and juice, fish sauce, and brown sugar. Set aside.
In a large sauté pan over medium heat, add canola oil. Add garlic, ginger, jalapeño and red pepper flakes (if using). Cook for about 30 seconds, until aromatic. Add cooked lentils to the pan, and mix to combine.
Add in the lime/fish sauce mixture and stir until the sauce has been absorbed. Adjust flavours to suit your taste by adding more lime or fish sauce. You want to have a balance between the lime and salty fish sauce.
Serve lentil larb moo on lettuce leaves with carrots, cucumbers, scallions, or any of your favourite vegetables. Serve with lime wedges on the side to squeeze on the lettuce wraps.