Kudus, who joined the Hammers from Ajax this summer for £38million, scored West Ham’s second goal as they beat the Gunners 3-1 in the fourth round of the Carabao Cup.
It was a brilliant effort from the forward, who controlled a long ball and cut inside before finding the bottom corner.
Kudus has started just one Premier League game since joining and he has carefully integrated him into the team, but Moyes believes the Ghanaian is starting to show his best.
“As we saw he scored a good goal against Newcastle,” said Moyes. “He played well at the weekend as well.
“We are beginning to find ways of getting him closer to starting and playing. He is looking very good.
“I thought the forward players did a really good job tonight, all the front boys.
“Then for long periods we had to be in a good defensive organisation and shape to play against Arsenal. I thought for the most of it we coped well.”
West Ham are now into the quarter-finals of the Carabao Cup and, after winning the Europa Conference League last season, Moyes has praised his side’s ability in cup competitions - even if he is hungry for that to translate to the league.
“Maybe we are becoming quite a good cup team possibly,” he said. “I want to be a really good league team if I can be.
“But, if I can’t quite do that, then I have to do well in the cups if we can. Now, we have only won a game against Arsenal tonight, you don’t get any trophies tonight for that.
“But we said that a little bit last year when we were on the run to win the Conference League. You can only take the game and see what’s going to come next. The draws in the cups are always hugely important.”
Wednesday’s game was Rice’s first visit back to the London Stadium since leaving for Arsenal this summer.
The midfielder, who was sold for £105million, was met with a mixture of boos and applause by West Ham fans when he came on in the second-half.
“I think everybody is entitled to their form of opinion,” said Moyes. “There isn’t a person in this stadium tonight who doesn’t recognise Declan Rice is a top football player.
“But there was a lot of West Ham supporters in there tonight who probably hoped that he didn’t do so well and their team won. From that point of view, you are always going to get mixed feelings and different opinions.”
“I couldn’t be sure yet [if he will be fit for Brentford on Saturday],” he said. “He just felt his knee and we had him scanned. He seems okay, but we are just going to see how he is tomorrow really.”