Strong running by centre Owen Farrell, son of Saracens and England centre Andy, made Wallace's first try and then he ran forty metres for his second as the Welsh youngsters saw a 15-3 interval deficit turn into a 29-3 and finally 32-3 scoreline.
Wales started strongly and Rhys Ruddock's pack kept their side on top in the opening ten minutes. England outside half Tom Catterick and Wales No.10 Ian Smerddon swapped penalties before England's left wing Reuben Haile crossed for the game's first try with a forty-five metre run after Wales had spilled a pass.
The home side took a firm grip of the game just before the break when they converted their second five metre line-out into a try for scrum half Matthew Keyte to stretch their lead to 15-3 with a Catterick conversion. Then came the two Wallace tries, both of which Catterick converted, before the outside half added a second penalty to extend the English lead to a massive 29 points.
Wales rallied at the end and finished on a high note with a try from replacement hooker Luke Lewis, who crossed from a quick tap penalty. Fullback Dean Gunter added the conversion.
Wales meet the Italians on Sunday (France beat Italy 10-8 in their clash) before rounding off the tournament against the French.
England U16: Tries: J Wallace (2), R Haile, M Keyte. Cons: T Catterick (3). Pens: T Catterick (2)
Wales U16: Try: L Lewis. Con: D Gunter. Pen: I Smerddon
Dean Gunter (Mountain Ash CS/Blues North)
Josh Smart (Tasker Milward School/Scarlets)
Ben John (Ysgol Gwyr/Ospreys)
Scott Williams (Ysgol Dyffryn Teifi/Scarlets)
Will Rose (Ysgol y Cymer/Blues North)
Ian Smerddon (Y Pant/Blues North)
Tom Rowlands (Whitchurch HS/Blues South)
Richard Powell (Cyfartha HS/Blues North)
Ieuan Davies (Treorchy CS/Blues North)
Tristan Davies (Ysgol Bro Myrddin/Scarlets)
Tom Payne (Rhydyfelin CS/Blues North)
Rhys Ruddock (Bishopston CS/Ospreys, Captain)
Edward Siggery (Queen Elizabeth HS/Scarlets)
Guy Jones (Gowerton School/Ospreys)
Garrick Legge (Coedylan CS/Blues North)
Chris Phillips (Hawthorn CS/Blues North)
Luke Lewis (Bryngwyn CS/Scarlets)
Joe Davey (King Henry VIII/Dragons)
Matthew Defilippo (Coedcae CS/Scarlets)
Ellis Lloyd (Maes-yr-yrfa/Scarlets)
Aled Davies (Ysgol Bro Myrddin/Scarlets)
Chris Lewis-Pratt (Wellington College)
Rhys Howells (Wellington College)