Oily, citrusy dressings are amazing for nutrient absorption in my experience. I usually go with things like walnut oil/lime juice and seasonings for salads. Another easy way to up protein and iron is learning to "scramble" tofu, and then have it with frozen spinach. Tastes great, easy to make, inexpensive, and plenty of iron/protein in a simple meal. I forgot - hummus! A giant container of tahini is cheap, garbanzo beans either dried (takes overnight preparation, but way cheaper) or canned (more convenient) are both cheap enough, and hummus is incredibly easy to prepare so long as you have some sort of food processor. Amazing protein and vitamins.