No. This always means that one needs more time and that the other person needs to wait a bit. For another helping, you would probably ask if you could serve yourself again, a question to which any Portuguese person would reply something along the lines of, "Of course! Eat! Eat!" XD
When you are looking for the word for the unit of time measurement equivalent to 1/60th of a minute, it is always «um segundo».
The words «segundo» and «segunda» are adjectives that mean "second." You can also turn them into nouns; for example, a woman who says, "I am the second one in line," would be «Sou a segunda na fila.».
Also, «segunda» can be short for «segunda-feira» = "Monday."