An individual cells height and width are tied to the column width and Row height.
You can use merged cells to make bigger cells, but this can create issues with selecting rows/columns where merged cells exist.
Your question suggest you have two tables on the same worksheet. While in some cases this seems like a great idea, it can create any of several issues, like when disparate formatting is required.
Tables are best places on individual worksheets, especially when for reporting or dynamic data tables. (Fixed reference tables can be combined to a single worksheet usually without any problems since they are not generally printed.)
