The 21-year-old edged out Knicks rookie Obi Toppin and Pacers rookie Cassius Stanley to win it all during halftime of the All-Star Game ... showing off his INSANE hops in the process.

Simons' first dunk may have been the most creative of the night -- he grabbed the ball off a mini hoop 2 feet higher than the rim and brought it home for the slam.

There was a bit of controversy in the first round -- many believed Stanley's between-the-legs slam deserved a better score ... but ultimately, scored lowest out of the first three dunks.

Simons' second dunk was a tribute to one of his idols, Tracy McGrady -- throwing on a T-Mac throwback Raptors jersey for a one-bounce 360 dunk, which was good enough to earn him a spot in the finals.

Simons secured the win after his lips came within inches of the rim on his last attempt ... and even though his goal was to actually make contact with the rim, but at least it was enough to take home the hardware.

"In practice, I never actually kissed the rim, but I was like ... 'I gotta commit to it,'" Simons told the media after the contest.

"I tried to put a mouthpiece in last-minute, but it didn't fit in my mouth. I just scratched, and I'm just going to emphasize the smooch face so people know I'm next to the rim and trying to kiss it."