Microwave beans on high for 2 minutes, or until tender. Transfer to a bowl of ice water to cool.
Add beans, shallots, thyme, lemon juice, lemon zest, salt, and pepper to a food processor and pulse to combine. Slowly add 1/2 the olive oil as you pulse. Add more oil if you like your purée less thick.
Spoon purée onto bread rounds. Add a layer of feta, then radish slices, and finish with some cracked pepper and a drizzle of oil. Serve.