Mulcair and Wall sat down Monday in Wall's office in the Saskatchewan legislature.
They emerged from the meeting to speak to reporters separately, but both men describe the chat as positive.
"Mr. Mulcair has got his views on certain things," said Wall.
"We agreed on a number of issues, we disagreed on a number of issues, but I appreciate the fact that he wanted to meet to talk about them.
"Politics is about building relationships and he's applying to be the prime minister of Canada and I think building a relationship with the leader of the Opposition federally, someone who might be the prime minister, is important for Saskatchewan to do as well."
Mulcair said he and Wall are on the same page when it comes to the scandal-plagued Senate.
"We started off with an easy one where we agree a great deal, which is on the Senate, that it's time to stop kidding ourselves that the Senate can be reformed," said Mulcair.
"Premier Wall has seen the different iterations, he's worked with other premiers over a number of years now, and he's seen the Senate, what it represents as a problem.
"When a premier of a province wants his province's voice to be heard, the last thing he needs is several senators who purport to be from his province, following a party line dictated by the prime minister's office, so that's an additional argument in favour of Senate abolition."
Mulcair said the two also agreed that diversity is important in Canada's economy.
The Opposition leader said the premier appreciated that the NDP's preference for development of natural resources is building a pipeline to carry western oil to the east coast.
TransCanada (TSX:TRP) Corp.'s Energy East Pipeline project, which still has to clear regulatory reviews, would ship up to 1.1 million barrels of crude per day from Alberta to Quebec in 2017. A 1,400-kilometre extension would be built to ship oil to the Irving Oil refinery in Saint John, N.B., a year later.
But Mulcair and Wall disagreed on some big issues, including the Keystone XL pipeline.
Wall supports building the Keystone XL pipeline, which would carry oilsands bitumen to Gulf Coast refineries. He said it's an important project for Canada.
"I don't think we've changed his mind on Keystone," said Wall.
"I just wanted to point out, though, that he talks about this pipeline, its construction, as only benefitting the United States. That's not true.
"You know before Keystone was held up by the (U.S.) administration, they were beginning to stage for construction right near Shaunavon, right in Saskatchewan they're going to be building. There'll be jobs created because of Keystone."
Earlier this year, Wall accused Mulcair of betraying Canadian interests when the NDP leader criticized Ottawa's environmental record and the Keystone XL pipeline while speaking in Washington.
Wall has also criticized Mulcair for what the premier called divisive comments that suggested booming oil and gas resources in the West have inflated the dollar and hurt central Canada's manufacturing sector. It's a scenario dubbed Dutch disease, a term coined in the Netherlands when a natural gas find in that country led to declines in manufacturing in the 1960s.
Last year, Mulcair angered western premiers by dismissing them as "messengers" of Prime Minister Stephen Harper.
At the meeting, Wall gave Mulcair a copy of a recent study that suggests higher commodity prices have had a benign, if not positive effect, on Canada's manufacturing industry.
But Mulcair said the two didn't need to talk about burying the hatchet Monday.
"The meeting went so well and it was so friendly and so open and, again, on something like Keystone XL, he knows my position," said Mulcair.
"The last thing I want is to ship 40,000 Canadian jobs to the U.S. I want to create them in Canada. But he was thankful for our reaction to the Energy East proposal because he sees that, at least, as a way of getting a large amount of petroleum products to market and lower the gap in the price, so that's a good thing on which we can agree.
"We tended to concentrate on what we agreed and where we disagreed, we talked about it very openly."