Not sure about who would give you a lesson but if you could get across to Tofino on Vancouver Island there are certainly flights available to land on mountain lakes, I did one with Atleo Air but quite a few floatplanes operate out of Tofino. We flew round the glacier, landed on a remote lake then out to sea and watched whales, an experience of a lifetime. Very sadly the pilot Damon York, a super chap was killed in a tragic accident not long after.