Place the lentils, water, and salt in saucepan, bring to a boil, lower heat, cover, and simmer for about 45 minutes, until water is nearly gone and lentils are very soft, with splitting skins.
Sauté the onion and carrot in oil until soft, about 5 minutes.
Mix the lentils, onions, carrots, pepper, and optional soy sauce in the large bowl, then mix in the ground oats and bread crumbs.
While still warm, form the lentil mixture into patties, which can now be frozen, refrigerated (for up to 5 days), or cooked immediately.
Cooking (2 possibilities):
- In a frying pan, heat a bit of oil, place a burger on top, and fry until brown, 1-2 minutes. Repeat on other side and serve.
- In a 400º oven, bake the burgers on a greased baking sheet until light brown, about 15 minutes.