Can I catch Pokémon with flawless IVs?
Absolutely, though there's no sure-fire method of doing so. You'll have to get to a catch combo chain of at least 31, then continue to catch Pokeémon of the same species until you see the 'Best' rating for each of the IVs.
It's worth noting that your chances of catching a flawless Pokémon don't increase the more Pokémon you catch after you've reached the max catch chain combo score of 31. Instead, you'll continue to get Pokémon with the four maxed IVs and will have a standard chance of the two remaining IVs being perfect too.