Step 1Combine the oil and zest in a saucepan. Cook over low heat 10 minutes. Don't allow to simmer. Remove from the heat and leave for 30 minutes. Strain out the zest.
Step 2Strip the leafy green parts of the chard from the stems. Set the stems aside for another use.
Step 3Blanch the chard in boiling, lightly salted water. Cook until the chard is al dente, with no trace of metallic rawness, usually about 1 minute.
Step 4Lift the leaves from the water and place in ice water. Drain and layer between towels to dry.
Step 5Place the chard in a 3-quart saucepan or 12-inch skillet. Drizzle with 3 to 4 tablespoons of the lemon oil and set over medium-low heat. Stir and fold until the chard is warm and coated with lemon oil. Salt to taste. Serve hot, warm or cold.