Peel potatoes and cut them into halves. Then cut the received pieces into thin slices. Sprinkle with salt.
Peel the onion, and chop it into small pieces.
Cut the tomatoes into middle pieces with a sharp knife.
Pour 2 tablespoons of vegetable oil into a frying pan. Heat it well with medium heat.
Put the potato slices on the hot frying pan and fry them for 5 minutes, stirring constantly.
Add the chopped onion to the frying pan also, and stir it well with potatoes. Cover the pan with a lid and reduce the heat. Continue frying with stirring it occasionally.
Break the eggs into a large bowl and whisk with a fork until the homogeneous mixture. Season with salt and ground pepper to taste.
When the potatoes and onions are done, add them to the bowl with eggs mass.
Also, add the tomatoes and peas to this bowl too.
Add the remaining spoonful of vegetable oil to the clean frying pan and heat it well with medium heat, approximately 1 minute.
Pour the mixture of eggs and vegetables from the bowl into the hot frying pan. Reduce the heat and fry it over low heat for 15 minutes.
When the liquid on the surface of the omelet will be evaporated, turn it over and fry for another 5 minutes.