Symbolism, Imagery, Allegory
When Lindo was forced to marry her bratty man-child of a hubby, the ceremony was marked with the lighting of a two-ended red candle. If the candle remained lit throughout the marriage night, the matrimonial bond was regarded as complete, and it was death-do-us-part time.
To ensure that this candle burn through the night, a servant was set to guard it.
But Lindo decided to take her fate into her own hands. After all, she'd just come to the conclusion that her strength was like the strength of the wind:
I asked myself, what is true about a person? Would I change in the same way the river changes color but still be the same person? And then I saw the curtains blowing wildly, and outside rain was falling harder, causing everyone to scurry and shout. I smiled. And then I realized it was the first time I could see the power of the wind. I couldn’t see the wind itself, but I could see it carried the water that filled the rivers and shaped the countryside. It caused men to yelp and dance.
I wiped my eyes and looked in the mirror. I was surprised at what I saw. I had on a beautiful red dress, but what I saw was even more valuable. I was strong. I was pure. I had genuine thoughts inside that no one could see, that no one could ever take away from me. I was like the wind. (I.3.45)
So what better was to flex her newly-found strength than by blowing out her marriage candle (using her very wind-like breath)? By extinguishing this candle, Lindo asserts that she will not be spiritually linked to her new hubby...and that making her own fate is far preferable to waiting around and seeing what fate might have in store for her.