Rav Meir Mazuz (contemporary) ruled that if a person ate a food which causes thirst such as couscous, which is often very dry he does not then recite a Beracha over the beverage he drinks to quench his thirst. The Rabbis reasoning is that since the food is what necessitated drinking, the beverage is, in a sense, "Tafel" (secondary) to the food, and so we apply the general rule that a Beracha recited over the primary food in a combination covers the secondary food. Hence, the Beracha recited over a dry or salty food covers the beverage that one then needs to drink to quench his thirst which was caused by that food.
Hacham Ovadia Yosef, however, in his Yabia Omer, disagrees with this position. In his view, the fact that a food caused the need to drink does not make the beverage secondary to the food, and therefore, the beverage requires a separate Beracha. Of course, if one eats bread, then beverages drunk during the meal do not require a Beracha, because they are all considered part of the meal, which is covered by the Beracha of "Hamosi" recited over the bread. But in other cases, drinks are not covered by the Beracha recited previously over food, even if it was the food which necessitated drinking. This is, indeed, the accepted practice.
Summary: If a person ate food which caused him to feel thirsty, thus necessitating drinking, he must recite a Beracha over the beverage, and we do not consider the beverage covered by the Beracha recited over the food.
