In a food processor, add the onion, garlic, parsley, spinach, sunflower seeds and chickpeas. Pulse for about 5 seconds, scrape down the sides, then blend again for 5 more seconds. Careful not to over blend. The chickpeas should be finely chopped but not mushy. It will make the burgers mushy if you over blend the chickpeas.Transfer the mixture to a large bowl then add the spices, lemon juice and chickpea flour. Stir to evenly combine. If the mixture appears too wet, add more chickpea flour a tablespoon at a time as needed. Using your hands, scoop out about 1/3 cup of the mixture and form into patties.Warm olive oil a skillet over medium heat. Cook the burgers for about 7 minutes on each side, until light golden brown. Alternatively you can bake them in the oven at 400°F for 7 minutes on each side.Prepare the tahini sauce by combining the ingredients in a small bowl. Add 3 tablespoons of water then whisk until smooth. Continue to add water one tablespoon at a time until desired consistency is reached. Add salt to taste, and/or more maple syrup if desired.Serve burgers warm with tahini sauce, lettuce and/or red onion on toasted whole grain buns and enjoy!