Cucumber and tomato should be eaten separately, otherwise cucumber will destroy vitamin C in tomatoes, not only tomatoes, but basically all foods rich in vitamin C should not be eaten with cucumber.

You can eat tomatoes in the morning, cucumbers at noon and tomatoes or cucumbers at night.

Give you a copy of my current cookbook:

Breakfast: a bowl of steamed eggs, a tomato and a bowl of milk cereal.

Lunch: one cold cucumber and fungus (2 cucumbers and proper amount of fungus) and two boiled potatoes.

Dinner: Boiled vegetables, tomatoes or fruits.