That the referenced item is important. When sorting potatoes for sale, the smallest ones are typically tossed aside as being not good enough to sell.
something or someone insignificant. An inconsequential amount
Cowboys loved a colorful phrase! This means mean, contemptible, worthless. You wouldn't want to hear a cowboy say you were small potatoes.
It means someone is telling you a small hint to remind you of something
I think you mean "no small potatoes" or "no small feat" - in slang "oats" refers to feeling young, frisky, and reckless. "No small potatoes" is money slang, meaning something costs a lot. "No small feat" means that something is a big feat, or a big accomplishment.
It's what you say when you meet someone unexpectedly such as: "Hey Joe" "What's up. It's a small world isn't it?"
It means you should be willing to risk a small amount in order to get a larger amount back.
It means by a very small margin, as in "it was nip and tuck whether we would win the game or not."
It is not an idiom, it means your nose is itching.
It's not really an idiom. It means "what are you thinking about."
RFP is not an idiom. It's an abbreviation.
"Sieve" is not an idiom. See the related link.
It's not an idiom. It means the tip of your nostril.