Put the lentils and the teaspoon of salt in a large saucepan. Add water to just cover the top of the lentils.
Bring to a boil and cover the pot. Turn down to medium-low heat.
Cook 20 minutes or until liquid is absorbed and the lentils are tender but not mushy. Set lentils aside.
In the meantime:
Heat oil in a skillet over medium-high heat.
Brown the sausage on all sides. Set aside.
Add the prepared onion, bell pepper and mushrooms to the pan. Cook for about 10 minutes. Quite a bit of liquid will cook out of the mushrooms.
Cut up the "sausage" into small chunks.
You will have a lot more, of everything, than what is shown on the plate in the photo above. This is just to show you the wonderful ingredients after they are cooked.
Now place some lentils, bell peppers, onion, mushrooms, "sausage" and salsa down the center of a tortilla. Fold in each side to keep the ingredients from falling out and roll up the burrito. You can see in the photo what they will look like.
You can eat right away or keep in a tightly covered glass container in the refrigerator for 3 days.
Heat each burrito in the microwave for 15-20 seconds or bake on a cookie sheet at 350° for 20 minutes.