Radishes need to grow quickly enough to avoid being invaded by root maggots or becoming hot and tough, so they need plenty of cool, moist soil. They are a perfect vegetable for growing in the spring or late fall. The fact that they mature in 30-something days makes for a rewarding effort in the garden when there isn't much of anything else growing. OrganicGardening gives some great tips on growing radishes too.
But what to do with these guys other than putting into a salad? Here's what I do. It's not much of a recipe; pretty much more of a procedure:
Toast a somewhat thick slice of peasant/rustic bread.
Butter it. (THIS is the key ingredient. Don't skip this step.)
Layer thinly sliced radishes over the entire slice.
Sprinkle with kosher salt. (Table salt would work but would not taste quite the same.)
Enjoy, and then find yourself making another helping.
It's the first part of June here, and the radishes are still growing strong. So I've kept up my succession planting. We've had an extremely damp, cool spring which has probably helped. I know that once our temperatures start climbing, the radishes will just be a memory until fall.