Set lower limit to incoming new channels in LND
If you look at lnd.conf (or in particular at the sample-lnd.conf line 138) you will see the following:

; The smallest channel size (in satoshis) that we should accept. Incoming
; channels smaller than this will be rejected, default value 20000.
; minchansize=


which means if you remove the ; and set a value in satoshis your node will reject smaller channels.

After changing lnd.conf you have to restart your node and then it should behave in the way you want