an onomatopoeic/mimetic word describing round, bright eyes or small tight curls (e.g., 'big round eyes').
赤ちゃんはくりくりした目でこっちを見ている。
The baby is looking this way with big, round eyes.
彼女のくりくりの髪型がとても可愛い。
Her curly (small-ringlet) hairstyle is very cute.
うれしくて彼はくりくりと目を輝かせた。
He brightened his eyes (made them look round and lively) with happiness.