Not much is known about Tiny. She, we assume, was caught trying to steal technical components from Dag Duh Dug's ship on a supply run. Slyth took a shine to her and took her on as a 'pet'. Despite Dag's protests he eventually warmed to the tiny jawa and nicknamed her "Tiny". Tiny eventually took a shine to Hibbity Jibbity and follows him around constantly.
In addition to the usual scavenging Jawa's are proned to do she's a masterful thief. Whether it's picking a pocket or dismantling equipment for a quick getaway she's become a useful companion to Dag and his friends.