Asuna and Mina were born in the slums of the Fire Nation, right in its very capitol. They grew up on the streets. Orphaned from a young age (ten and eight), thanks to the death of their water-bending father and fire-bending mother during a faction raid on the building they were living in. They only survived thanks to hustling on the street, and that only went well because Asuna was a quick learner and smart witted.
Asuna, being the eldest, learned how to bend at age six when Mina was just four years old. Her mother had been the one to teach her some bending abilities before she passed away. She became a mother-figure for her sister younger sister after that and did all that she could to teach her to be as quick in wit and mind as herself. Mina idolized her sister, always following her lead and never questioning her actions. If it wasn’t for trying to copy Asuna, she would have never realized she was a bender. It took some time and she bloomed much later than her sister and didn’t fully manipulate water until she was eight years old.
That achievement was mute, due to the fact that they lost their parents that same year. Of course, the sisters were originally put in an orphanage, but Asuna was able to recognize that she and her sister would quickly be separated into different families and homes. Which is why she convinced Mina to run away with her, with little to no plan on what to do after they escaped. That’s how they ended up on the street, fending for themselves. Trying to eat and keep sheltered.
They started simple and with the first thing they could think of - begging. Then they upgraded to pickpocketing to make some extra cash in order to buy meals and clothing. This lead to conning, which grew into a full on act. Mina played the naive girl, falling into the clutches of some “big bad wolf”, before stealing his money and scampering off. Asuna’s gimmick was the desperate sister who would do anything in the world to help her sister. While the victims were distracted by Asuna’s company or tender care, Mina would steal everything valuable that they owned and fled to their tiny apartment. Asuna usually came home later, sometimes battered and bruised. Mina hated the idea of anyone harming her sister and pleaded for this gimmick to stop, but Asuna and Mina made such good money and were starting to get on their feet. So Asuna continued and Mina had to reluctantly follow through.
Little did Mina know, Asuna was quite capable of handling herself in sticky situations, often gaining her battle wounds from the fight she would engage in whenever a man lifted their hand to her. She did not tolerate being smacked around and naturally, they paid for trying to. However, one night she had ticked off the wrong man. He was a faction leader, newly appointed. In fact, he ran the faction that killed their parents in a raid many years prior. He had tried to do the cliche and beat Asuna up after she offered her services but Asuna acted quickly. She had escaped but not without stabbing the man directly in the right eye with a pencil she found on the table. After that, there was a village-wide search for her and her little sister. In an act of desperation and without giving Mina much details, Asuna sold a lot of the things that they couldn’t run away with. Taking their savings, she found a boat and bribed the owner to let them get on. She told the man that she didn’t care where he took them as long as it was away from there. That was how they ended up at Republic City.