Grind all the rub ingredients in a mortar and pestle until well blended. Combine the spices with the olive oil and limejuice then rub the tuna with the mixture and leave to marinade for 20 minutes. Place the tuna on an oiled grill and cook for a couple of minutes on each side making sure you keep it nice and rare.
Finely chop the onion, garlic, chilli and ginger and combine with the lime juice and leave to macerate for 10 min Dice the tomatoes.
Add the tomato & coriander to the onion mixture. Add the olive oil and the seasoning.
Skin the avo’s and remove the pips. Mush the flesh up with a fork. Mix in the rest of the ingredients. Season to taste. The guacamole may need more lemon/lime juice depending on the avo’s.