Preheat oven to 350 degrees.
make the ramp pesto. Cut the roots off your ramps. While holding a paper towel, grab the bottom white part of the ramp and gently strip away the dirty outer layer. Give the ramps a good wash, and chop fine. In a food processor puree the ramps with the walnuts. Add just enough olive oil to make a smooth paste and season with salt and pepper.
Spread ramp pesto evenly over flat bread, leaving a crust. Layer on sliced tomatoes and cook in the oven for about 10 minutes.