Salads: I often eat my salads with no dressing, as I find the taste of a mixture of veggies and Romaine lettuce (not that nutrient-deficient iceberg stuff) tasty as is. If I do use a dressing, it's a basic vinegrette (you could just use a sprinkle of olive oil and some balsamic vinegar, for example).
You can find more "natural" salad dressings in health food stores.
For oatmeal, I sprinkle on flax meal and use maple syrup (not the artificial "maple-flavored'syrup crap, but REAL maple syrup from tree sap), or agave nectar (a low-glycemic natural sweetener from the same cactus that tequila is made from), or just some dried fruits, usually raisins.
You could also sweeten it by using apple juice for part of the water.
Also, steel-cut oats are naturally more flavorful than rolled oats, IMO, and taste a bit nuttier (as well as having a more appealing texture).