You have to think about miRNA as transcriptional and post-transcriptional regulators of gene expression. So, if they can match the seed sequence, they may repress or terminate the respective mRNA strand. And, since the DNMT and other epigenetic regulators, being proteins, also share the similar machinery of transcription and translation, the miRNA can definitely affect them. There are multiple publications on this aspect available now.
Indeed, miRNAs are epigenetic regulators acting over DNMTs and different histone modifiers. miRNAs can as well being regulated by DNA methylation on CpG island close to their encoded region, or even though the methylation at the promoter area of the gene in which the miRNA is encoded.