The unit of measure is "grammo", plural "grammi"; in this case they are "made of" what they measure, so you don't put the article. For instance "un litro d'acqua" (one liter of water), "un chilo di carne" (one kilogram of meat).
You can also see it here:
"Dieci grammi di riso" - Ten grammes of rice
"Dieci grammi del riso" - Ten grammes of the rice
In Italian, they just make the preceding vowel shorter and the consonant longer. :) It is the difference, for example, between "ninth" and "grandmother"/"grandfather": «nono»/«nona» and «nonno»/«nonna».
That's not a whole lot of rice. You'd get more rice in one of my great-aunt's cabbage rolls.
Actually, you are absolutely right because «riso» or «risata» in Italian also means "laughter." XD I did the same not too long ago
How do uou say "ounces". Yes, I know Italy does not use ounces. I live in USA.