Pat the prawns very dry first. That's particularly important after defrosting or they'll release water and steam.
Mix the prawns with ½ tbsp olive oil, sweet paprika, smoked paprika, oregano, pepper and salt. I'd leave the garlic out initially so it doesn't burn.
Get a large pan very hot. Add the remaining ½ tbsp oil and prawns in a single layer. Cook about 60–90 seconds, flip, then add the garlic and chilli. Cook another 60–90 seconds, just until the prawns are opaque and curled. If using tomatoes, blister them in the pan before the prawns and add them back at the end.
Turn the heat off and immediately add lemon juice, zest and parsley. Toss everything through the paprika-garlic oil.