With a vegetable peeler, peel skin of cucumber in lengthwise strips, alternating and removing about half of the skin. Cut cucumbers in half lengthwise, and scoop out the seeds with a teaspoon. Cut each half lengthwise in 3 or 4 wedges, then crosswise into 2-inch lengths.
Bring a pan of salted water to a boil, add cucumbers, and simmer until almost tender, 3 to 5 minutes. Melt butter in a medium skillet over medium heat. Add cooked cucumbers, mint or dill, and pepper to taste. Cook until cucumbers are very hot, about 1 minute.