Trim the ends off the cucumber and cut it into 1-in lengths, then cut each piece lengthwise into thin slices.
Arrange the cucumber slices in a colander and sprinkle them with the sea salt. Set aside for 5 minutes, until the cucumber has wilted.
Wash the cucumber slices well under cold water and pat them dry with paper towels.
Quarter the cherry tomatoes and place in a bowl with the wilted cucumber. Finely chop the garlic.
Chop the lemon rind finely and place in a small pitcher with the juice from the lemon, the chili oil, chili flakes, dill and garlic. Add salt and pepper to taste, and whisk with a fork.
Pour the chili oil dressing over the tomatoes and cucumber and toss well. Let marinate at room temperature for at least 2 hours before serving,