Step 1Peel and trim the cucumbers. Cut in half lengthwise and scrape out seeds. Cut each half lengthwise into thirds or fourths so each strip is no more than one-half inch wide. Cut crosswise on the diagonal, alternating directions, to make small triangles.
Step 2Melt 1 teaspoon butter in a saute pan over medium-high heat. Add the pancetta and cook until crisp, about 7 minutes. Remove with a slotted spoon and drain on paper towels.
Step 3Wipe the pan completely clean with a paper towel. Add the remaining butter, then the cucumbers. Cook quickly, stirring, until the cucumbers are just wilted but still crunchy, about 2 minutes. Season with salt and white pepper to taste. Toss with the chives. Crumble the pancetta over and serve at once.