Stanza 1 Summary

Get out the microscope, because we’re going through this poem line-by-line.

While my hair was still cut straight across my forehead
I played about the front gate, pulling flowers.

To begin with, we know that this is a letter from a wife to her husband and that her husband is a merchant. (Thanks title! For more on that, check out "What's Up With the Title?".)
We can guess that the detail about having hair cut straight across her forehead implies that she's writing about herself as a child (perhaps at the mercy of a less-than-stylish young haircut, like those awful bowl cuts).
Additional details about her childhood include the memory of a specific event when she was pulling flowers out by the front gate where she lived.
Notice how the flowers seem reluctant to being picked. They aren't plucked, or picked even. They're "pull[ed]" from the ground, which sounds like they may have been reluctant to go.

You came by on bamboo stilts, playing horse,
You walked about my seat, playing with blue plums.

The speaker recalls when this boy (who we guess now to be her husband and the addressee of the letter) came by on stilts.
Apparently it caught her attention, because he was playing about and maybe even juggling some plums. Yeah, we'd notice that, too.
Also, notice the two different uses of "playing."
The first "playing" suggests that the boy (now husband) pretended to be (or to ride) a horse, while the second playing suggests something like juggling.
Also, we have two possible ways to read the word "seat." One could be, in the literal sense, a chair in which the girl sat. Another way to read it is as a synecdoche, a technique where a part of something (like the place where a person sits) is used to mean the whole of something (like the girl's house).

And we went on living in the village of Chokan:
Two small people, without dislike or suspicion.

We guess that these two didn't really have much contact after that encounter—at least for some time.
They "went on living," which suggests that time passed as they pursued their separate lives in a village.
(Geography note: Here the village is called Chokan, but this is a version of the Japanese name for the town of Ch'ang-kan, a suburb of Nanking. The town names are the result of Pound looking at Japanese translations of the original Chinese poem.)
The wife refers to herself and to her now-husband as "two small people," as though they didn't think of themselves as children at the time but, rather, maturing adults.
Still, they're not to adulthood quite yet. They're innocent in that they don't go about hating on people.