Put water in saucepan and bring to a boil. Add red lentils and reduce heat to a simmer – will take approximately 20 minutes to cook, uncovered. Remove from heat, drain excess liquid (if any) and allow to cool.
Combine oats, flour, flax, walnuts, salt and cinnamon in a large bowl and whisk together.
In a separate bowl, combine lentils, peanut butter, corn syrup, and vanilla. Blend with a whisk until fully incorporated.
Add the dry ingredients to the wet ingredients and mix fully. Fold in cranberries and chopped chocolate.
Press the mixture firmly into a 9 x 13 baking pan (parchment on top to keep your hands or utensils from sticking can help) and bake for 25 minutes.
When done, allow to cool and cut into desired bar-shaped size.