This recipe is from Vegetarian India: A Journey Through the Best of Indian Home Cooking ($35), Madhur Jaffrey.
4 cucumbers (ideally seedless cucumbers, labeled Armenian or Persian)
1 teaspoon lemon juice
1/4 teaspoon salt, or to taste
1⁄8 teaspoon ground roasted cumin seeds
1⁄8 teaspoon chili powder
2 teaspoons olive or peanut oil
1⁄8 teaspoon whole brown mustard seeds
1⁄8 teaspoon whole cumin seeds
5–6 fresh curry leaves or small basil leaves
Peel the cucumbers and halve them lengthwise. Arrange them on a plate, cut side up. Dribble the lemon juice over them as evenly as you can manage. Now sprinkle the salt, cumin seeds, and chili powder over them in the same even manner.
Put the oil in a small frying pan over medium-high heat. When hot, add the mustard seeds. As soon as they start to pop, a matter of seconds, add the cumin seeds and let them sizzle for a few seconds. Throw in the curry leaves and turn off the heat. Now tilt the frying pan and spoon the oil and spices evenly over the cucumbers. They are ready to be served.