For the burgers: Add the beans to a large bowl with the breadcrumbs, lemon juice, oregano, salt, pepper, garlic, eggs, onions and 2 tablespoons of olive oil. Mash with a fork or your hands until the mixture is homogeneous. Portion into 6 patties and refrigerate for 1 hour.
For the mayo: In a small bowl, mix the mayonnaise, sundried tomato puree, pepper, salt, garlic and lime juice.
Heat a medium non-stick pan over medium-high heat and add the remaining 2 tablespoons olive oil. Cook the burgers until golden brown, 3 to 4 minutes per side. Slather each side of the bun with mayo, then top the bottom bun with the lettuce, burger, tomatoes, pickles, pickled jalapenos, another lettuce slice and top with the top bun.