Heat olive oil in a saucepan over medium heat, Cook and stir onions in hot oil until soft but not browned, about 5 minutes. Add peas, tomatoes, potato, dill, salt, and pepper. Add water if there is not enough liquid from tomatoes.

Stir thoroughly and bring to a boil. Lower heat and cook, partially covered, until peas and potato are soft, about 30 minutes. Make sure that any remaining water from tomatoes has evaporated before serving.