Place lentils in a medium saucepan, add 2c water and bring to a boil.
Stir, reduce heat to low, cover and simmer for 20 minutes.
Drain thoroughly and set aside.
Prepare bulgur according to package instructions.
Fluff with a fork and set aside to cool.
Combine ground flax seed with 3Tbsp of boiling water and whisk to combine.
Set aside until thickened, about 10 minutes.
Heat 1.5Tbsp olive oil in a large saute pan over medium high heat.
Add diced onions and cook, stirring frequently, until transparent and browned,
about 8-12 minutes.
Add garlic and cook for 1-2 minutes more.
Add greens and cook 2-3 minutes, until wilted. Set aside.
Add lentils, bulgur, walnuts, flax seed mixture, 1.5Tbsp olive oil, salt, pepper, crushed red pepper and paprika to the bowl of a food processor.
Process for 25-30 seconds, until mixture is well incorporated
but some larger pieces still remain.
Add cooked onion and green mixture.
Process for 10-15 seconds more.
At this point, taste the mixture and adjust salt and pepper as needed.
Use your hands to form standard-sized burgers, about 3" across, and place on
parchment-lined baking sheet.
I found that the burgers cooked best when left to set up for 20-25 minutes beforehand.
Pan fry in a bit of olive oil, cooking over medium high heat for 6-8 minutes on each side, or bake on a parchment lined baking sheet at 350 for 18 minutes,
flipping halfway through.
Extra burgers can be kept uncooked, wrapped in parchment and refrigerated for 2-3 days or frozen for up to a month.