Can I say:
1 Can I point to the name of a dish on the menu and say "This is the spinach lasagna. / This is the pizza".

2 Can I say :
- He also be angry / there / a teacher

Question

Can I say:
1 Can I point to the name of a dish on the menu and say "This is the spinach lasagna. / This is the pizza".

2 Can I say :
- He also be angry / there / a teacher

Answer

To answer your question to 1. Yes you could say that.  It would be more natural if you were pointing to a photo of the dishes rather than text.
To answer you question to 2. The aux verb 'to be' is not conjugated correctly.  It should be 'He is also angry/there/a teacher

Answer

1. If you have the lasagna in your hand you can say 'this is the lasagna', if not, perhaps, 'we have the spinach lasagna'.

2. H is also angry/a teacher/there