Combine the ground flaxseeds with the water and let it sit for at least 5 minutes.
Heat some oil in a medium-sized pan and sauté the onion and the garlic for 2-3 minutes. Set aside. Heat some more oil and sear the mushrooms for about 3 minutes.
Mash the chickpeas with a fork, leaving some intact for texture. In a bowl, combine the chickpeas, the pumpkin puree, and the oats. Add the Italian seasoning, the paprika powder, the mustard, the flaxseed-water mixture, and the sautéd onion and the garlic. Season with salt and pepper. Form four burger patties.
Heat some oil and cook the patties for about 2-3 minutes on each side. Put the vegan mayonnaise in a small bowl and stir in the minced garlic.
Serve the pumpkin pattties on whole wheat buns with lamb's lettuce, mushrooms, garlic mayonnaise, and top with them with pomegranate seeds. Serve with potato wedges.