"Our philosophy is to be competitive, committed and physical in every game while respecting the laws, officials and fellow players," said Lewis.
"We have made it a priority to challenge the opposition with the ball in hand through creative, imaginative play. We will of course strive to be ahead on the scoreboard come the end of the game but not without fulfilling the above objectives.
"We have a clear vision for how we want to play the game and we believe success, not only for this side, but for the sustainability of the national game will come from that."
Lewis has selected Ospreys wing Dafydd Howells as his skipper for this game but is looking for leadership qualities throughout the side.
"Dafydd is an outstanding player with a very promising future ahead of him," said Lewis.
"He has speed, elusiveness and power within his armoury and showed on our tour of South Africa last summer just what he's capable of with a try against France and a hat trick against England - a great achievement at any level of the game.
"He is already playing for Neath and training with the Ospreys and I'm sure he will lead by example on Sunday, while a number of other players will have responsibility for various aspects of the game such as the line-out, scrum, defence and at half back.
"We are pleased with the development of this group of players, both individually and collectively, but you only really get an accurate assessment from seeing how players react to a match situation and the training game against Leicester Academy last week was a helpful exercise, but obviously Sunday's game and the England match in a fortnight (St Helens, Sunday 10 March) will be the real yardsticks."
Lewis travels to Japan with Robin McBryde's senior squad in June in a bid to further bridge the gap to senior international rugby.
"With the likes of Tom Prydie, George North and Harry Robinson having stepped straight from the Wales Under 18 set-up into the national squad environment, the need to prepare our young players for that transition is more vital than ever," added Lewis.
"The Welsh Rugby Union places a huge importance on rugby development, and under Head of Rugby Joe Lydon the performance development department is working closer than ever with the national coaches. I will be observing the national coaches in the lead-up to the tour and in Japan, and working closely with them in order to filter down their philosophies and practices to the next generation of Welsh players."
Wales Under 18 team v France Under 18 - Sunday, 24 February - 2.30pm - St Helen's, Swansea
Steffan Evans (Scarlets / Ysgol y Strade / Kidwelly); Dafydd Howells (capt, Ospreys / Neath Port Talbot Coll / Abercrave), Aled Summerhill (Blues / Coleg Morgannwg), Craig Woodall (Scarlets / Amman Valley), Josh Adams (Scarlets / Coleg Sir Gar / Pontyberem); Angus O'Brien (Dragons / Caerleon Comp / Caerleon), Dan Brooks (Ospreys / Llandovery Coll/ Bonymaen); Dillon Lewis (Blues / Ysgol Gyfun Garth Olwg / Pontypridd), Torin Myhill (Scarlets / Coleg Sir Gar / Burry Port), Javan Sebastian (Scarlets / Queen Elizabeth High / Carmarthan Athletic), Josh Helps (Scarlets / Dyffryn Taf), Rory Thornton (Ospreys / Gower College / Bonymaen), Ollie Hitchings (Blues/ Cowbridge Comp / Glamorgan Wanderers), Oliver Griffiths (Dragons / Coleg Gwent / Crumlin), Tom Phillips (Scarlets / Coleg Sir Gar/ Llangennech)
Replacements: Callum Mitchell (RGC / Llandrillo College / Colwyn Bay), Ryan Elias (Scarlets / Bro Myrddin / Carmarthen Athletic), Alex Jeffries (Dragons / Coleg Gwent / Newport), Adam Beard (Ospreys / Neath College / Birchgrove), Jordan Collier (Ospreys / Neath Port Talbot College / Neath), Tom Williams (Blues / Treorchy Comp / Treorchy), Luke Price (Ospreys / Maesydderwen / Abercrave), Joe Thomas (Ospreys / Neath Port Talbot Coll / Morriston)
Ticket info: adults £5, Under 16s free, tickets available from Swansea RFC and by calling 01792 424242