I'm afraid that your image doesn't give us any identifiable features. The eggs aren't, by chance, on little stalks, are they?

Right off the bat, I can't think of a pest insect that might be found on both tomatoes and cucumbers.

Hello! Thanks for answer me...I've only seen the eggs on my tomatoes leaves..in the cucumber and chilli I only see that they eat the leaves and done holes in the leaves..

The Tomato Fruit worms eggs are whitish and the Tomato Hornworms eggs turn whitish just before the larva hatches. A couple of possibilities.