The Hull KR half-back set up the chance for Toby King to score the opening try with a dazzling break early on before adding the second with a confident piece of play.
Lewis was named man of the match to crown a memorable first outing at international level.
"He was good but can do a lot better," said Wane as he sat alongside Lewis and two-try winger Tom Johnstone in his post-match press conference.
"I know he's a lot more talented. He did really well for his first game against a big, athletic team. I'm fairly happy.
"I know he can play and has always been a running threat. Once I committed to him, that's it.
"He's conducted himself so well and is a credit to Hull KR and what they've done as a club.
"To come in there and sing that song with our team as an Englishman, there is nobody more proud than these two."
Lewis was handed his opportunity after captain George Williams received a two-match suspension for an incident in Warrington Wolves' final game of the Super League season.
Williams is also sidelined for next week's second Test at Huddersfield, meaning Lewis will get at least one more chance alongside Wigan Warriors half-back Harry Smith after a promising first outing together.
"As soon as that decision was made, it was all about Mikey and Harry," added Wane on the decision to double Williams’ ban for a frivolous appeal.
"He goes to all our video meetings and talks and gives his opinion just like George would.
"That's a really pleasing thing for me. He's fitting in really well and is a good lad."
England were made to work for the win against a Tongan side packed with NRL players.
Starford To'a and Tyson Frizell cancelled out the tries from King and Lewis in a hard-fought first half and it took two second-half efforts from former Wakefield Trinity winger Johnstone to end the tourists' challenge.
Tolutau Koula's try two minutes from time gave Tonga a glimmer of hope but Kristian Woolf's side fell just short in a repeat of the last meeting between the nations at the 2017 World Cup.
Wane felt the performance was a step in the right direction as England rebuild following their painful semi-final exit at the hands of Samoa at last year's tournament on home soil.
"It wasn't perfect but I thought it was a really good performance in patches, considering we've only trained together twice and we have a young half-back partnership," said Wane.
"I'm happy that we've won a Test match. They're a good team with a lot of NRL players. They're bigger athletes and a far bigger team than us.
"I do honestly know that we can improve massively on that. We did some good things but not for long enough periods yet."