If you are using the solid type coconut oil, heat it gently until it melts.
Purée the bananas, coconut oil, dates and salt together in a blender or food processor. Mix the dry ingredients together, then add them to the wet ingredients and mix them all together.
Spray a cookie sheet or cover it with parchment paper to make cleanup easier. Spoon the mixture on to the cookie sheet, one spoonful per cookie. You should get about 12 cookies, but it depends on the size you make them. Keep them well separated.
Bake the banana oatmeal cookies at 400°F for 10 minutes. Take them out of the oven to flatten them a bit with a spatula, then place the cookies back in the hot oven and bake them for another 10 minutes.