Rinse the lentils under cool water. In a pot, combine them with 450 ml of water and a pinch of salt. Bring to a boil, then lower the heat and simmer for about 25 minutes or until tender. Drain any excess water.
While the lentils are cooking, steam or boil the diced pumpkin and carrots for about 10-15 minutes until just tender but still crisp. Drain and set aside.
In a mixing bowl, combine the cooked lentils, cooked rice, honey mustard, and olive oil. Stir until well mixed.
Gently fold in the cooked carrots and pumpkin into the lentil-rice mixture.
Taste and adjust seasoning with salt and cracked black pepper as needed.
Spoon the mixture into bento boxes. Top with chopped cilantro and a sprinkle of sesame seeds if desired.
Allow the bento boxes to rest for 5 minutes for flavors to meld before serving.
