And if they are not big
It's very hard to determine exactly what's big and what's small in every case, but generally If it's clearly a piece of let's say pineapple, then u make a hadama even If it's in a bowl of kiwi (haeitz). and this being the only pineapple... If you have a bowl of diced fruits and you have no idea which is what fruit. Then you have problems, because you're not sure what Beracha to make. And it isn't always so simple what to do....
But I believe if you have a salad, and you have some very small diced fruits mixed into the salad, it can sometimes be a taful to the salad and the hadama on the veggies may be fine for that. Then if you have a scoop of tuna, which is on top, not mixed in, you would have to make a shehokol.
Bottom line: Hilchos Berachos is quite vast and often complex, I am not a Baki in these Halachos (one day Bezh) and nothing written here should be relied upon as a Halacha. Discuss it with your lor.