In a small bowl, cover the tomatoes with hot water and let them soak for 10 minutes. Drain them and squeeze out the excess water. Place them and all the other ingredients for the spread in a blender or food processor and puree until smooth. Add mayonnaise if the mixture is too thick. Set the spread aside.
In a large bowl, use a fork to flake the salmon. Stir in the remaining burger ingredients until well blended. Add more wheat germ if the mixture is too moist. Divide the mixture into eight equal portions and shape it into patties. Serve them on the slider buns topped with the tomato spread, onion, cucumber, and greens.