That COB is 63 watts maximum (36 volts x 1759-0 ma). You just multiply the forward voltage by the current. Which you can also measure with a cheap multimeter. (You have to put the meter in 10 amp setting and put it in series with the COB to get current, then reconnect the COB to power and measure voltage across the COB terminals.) If you run it with an 1120 ma driver it will be less power. Around (1120/1750) x 63 = 40 watts.
That’s just an approximation though, because at that current it will not drop 36 volts. It might be around 31 volts, so that would be 22 watts. It is difficult to predict without the manufacturers voltage & current graph. LEDs are not linear. They start making light when the voltage reaches a certain level and above that they make more light. But as you increase the current the forward voltage rises and as they get hot more of the light is infrared. So they make more light but the lumens/watt line falls off and gets flatter.
The best thing to do is to find their maximum current and then run them at 1/3 to 1/2 of that. You get a lot of lumens/watt and usually buying more COBs is cheaper over the long run. You have to pay to run these at least 12 hours a day, you know!
So I would recommend running it at 850 ma. The driver should be able to supply 36 volts, though it won’t actually put more than 31 volts across the COB. Don’t worry much about the wattage: You’re not going to run anyway near the maximum. If you tried to run them at 12 volts they would do nothing.
Beware of random power supplies on eBay or sitting around. They will almost all be constant voltage and will either not run the COB at all or blow it up if the voltage is too high.